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What are the AND/OR Operators used for?
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Section 1
(50 cards)
What are the AND/OR Operators used for?
The AND & OR operators are used to filter records based on more than one condition.
Can SQL update records in a database?
Yes, SQL can update records in a database
What happens if you omit the WHERE clause in the DELETE statement?
If you omit the WHERE clause, all records will be deleted!
Can a column contain duplicate Values?
Yes a column can contain Duplicate Values
Can SQL set permissions on tables, procedures, and views?
Yes, SQL can set permissions on tables, procedures, and views
Can SQL execute queries against a database?
Yes, SQL can execute queries against a database
What does the U in CRUD stand for?
Update, U in CRUD, stands for Update and is on of the four basic functions of persistent storage.
Can SQL create stored procedures in a database?
Yes, SQL can create stored procedures in a database
What is SQL?
SQL stands for Structured Query Language. SQL lets you access and manipulate databases.
What are the four basic functions of persistent storage?
The four basic functions of persistent storage can be defined by acronym CRUD
What does the D in CRUD stand for?
Delete, D in CRUD, stands for Delete and is on of the four basic functions of persistent storage.
Why are all Records updated if you omit the WHERE in the UPDATE Statement?
The WHERE clause specifies which record or records that should be updated. If you omit the WHERE clause, all records will be updated!
Where is the data stored in RDBMS?
The data in RDBMS is stored in database objects called tables.
Can SQL can insert records in a database?
Yes, SQL can insert records in a database
WHERE clause syntax:
WHERE Syntax: SELECT column_name,column_name FROM table_name WHERE column_name operator value;
What is the default order in the ORDER keyword?
The ORDER BY keyword sorts the records in ascending order by default.
What is the INSERT INTO Statement used for?
The INSERT INTO statement is used to insert new records in a table.
What is the SELECT Statement Syntax?
SELECT column_name, column_name FROM table_name; SELECT * FROM table_name;
Can SQL retrieve data from a database?
Yes, SQL can retrieve data from a database
What does the R in CRUD stand for?
Read/Retrieve (Select), R in CRUD, stand for Read/Retrieve (Select) and is on of the four basic functions of persistent storage.
Can SQL create new databases?
Yes, SQL can create new databases
Example of UPDATE statement
Update Example: UPDATE table_name SET column1=value1,column2=value2,... WHERE some_column=some_value;
Does the SELECT TOP clause has any utility on large tables?
Yes, the SELECT TOP clause can be very useful on large tables with thousands of records.
What can SQL do?
SQL can execute queries against a database SQL can retrieve data from a database SQL can insert records in a database SQL can update records in a database SQL can delete records from a database SQL can create new databases SQL can create new tables in a database SQL can create stored procedures in a database SQL can create views in a database SQL can set permissions on tables, procedures, and views
What is the SELECT Statement for?
The SELECT statement is used to select data from a database.
What is the SELECT TOP Clause used for?
The SELECT TOP clause is used to specify the number of records to return.
Can you have more than one statement to be executed in the same call to the server?
Yes, but a semicolon is needed to separate each SQL Statement.
What it the DELETE Statement used for?
The DELETE statement is used to delete
Example of INSERT INTO statement
INSERT INTO Example: INSERT INTO table_name VALUES (value1,value2,value3,...); INSERT INTO table_name (column1,column2,column3,...) VALUES (value1,value2,value3,...);
Can SQL create views in a database?
Yes, SQL can create views in a database
What is a table?
A table is a collection of related data entries and it consists of columns and rows.
What is the WHERE Clause used for?
The WHERE clause is used to extract only those records that fulfill a specified criterion.
Are SQL queries case sensitive?
SQL keywords are NOT case sensitive
What is the UPDATE Statement used for?
The UPDATE statement is used to update existing records in a table.
Example of OR operator
Example of OR Syntax: SELECT * FROM Customers WHERE Country='Germany' AND (City='Berlin' OR City='München');
How do you separate the duplicate Values from a Column?
You can list only the different (distinct) values, using the DISTINCT Statement
Can you have ORDER by Desc value?
Yes, To sort the records in a descending order, you can use the DESC keyword.
What is CRUD?
Create, Read/Retrieve (Select), Update and Delete are the four basic functions of persistent storage.
What is the Basis of SQL?
RDBMS is the basis for SQL, and for all modern database systems such as MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access.
DISTINCT syntax
SELECT DISTINCT column_name,column_name FROM table_name;
What does the C in CRUD stand for?
Create, C in CRUD, stand for Create and is on of the four basic functions of persistent storage.
Why does the SELECT TOP clause be useful on large tables?
Performance - Returning a large number of records can impact on performance.
What happens if you use the UPDATE statement without the WHERE?
All Records are updated.
Can SQL create new tables in a database?
Yes, SQL can create new tables in a database
What is RDBMS?
RDBMS stands for Relational Database Management System.
What is the purpose of WHERE in the DELETE statement?
The WHERE clause specifies which record or records that should be deleted.
What is the function of the Semicolon in SQL?
Semicolon is the standard way to separate each SQL statement in database systems that allow more than one SQL statement to be executed in the same call to the server.
Is select is the same as SELECT in SQL?
Yes, select is the same as SELECT since SQL is not case sensitive
Can SQL delete records from a database?
Yes, SQL can delete records from a database
What is the ORDER BY Keyword used for?
The ORDER BY keyword is used to sort the result-set by one or more columns. SELECT column_name, column_name FROM table_name ORDER BY column_name ASC|DESC, column_name ASC|DESC;
Section 2
(50 cards)
What are SQL constraints used for?
SQL constraints are used to specify rules for the data in a table.
What does the LEFT JOIN do?
The LEFT JOIN keyword returns all rows from the left table (table1), with the matching rows in the right table (table2).
What is the UNION operator used for?
The UNION operator is used to combine the result-set of two or more SELECT statements.
Does a PRIMARY KEY Constraint automatically has a UNIQUE constraint?
Yes, A PRIMARY KEY constraint automatically has a UNIQUE constraint defined on it.
What are the Aliases (AS) used for?
SQL aliases are used to give a database table, or a column in a table, a temporary name.
Example of INNER JOIN keyword:
Example of INNER JOIN keyword: SELECT column_name(s) FROM table1 INNER JOIN table2 ON table1.column_name=table2.column_name; SELECT column_name(s) FROM table1 JOIN table2 ON table1.column_name=table2.column_name;
Example syntax of SELECT TOP
SELECT TOP example syntax: SELECT TOP number|percent column_name(s) FROM table_name;
Is the FULL OUTER JOIN a combination of both LEFT and RIGHT join?
Yes, The FULL OUTER JOIN keyword combines the result of both LEFT and RIGHT joins.
What happens if there is no match on the left side with the RIGHT JOIN?
NULL - The result is NULL in the left side when there is no match.
IN Clause
The IN operator allows you to specify multiple values in a WHERE clause.
Can you have a lot of UNIQUE Constraints per table?
YES, that you can have many UNIQUE constraints per table, but only one PRIMARY KEY constraint per table.
Example of INSERT INTO syntax:
Example of INSERT INTO syntax: INSERT INTO table2 SELECT * FROM table1; INSERT INTO table2 (column_name(s)) SELECT column_name(s) FROM table1;
When creating a table how are tables organized?
Tables are organized into rows and columns; and each table must have a name.
What happens on the LEFT JOIN if there is no match in the right side?
NULL - The result is NULL in the right side when there is no match.
Example of creating a table Syntax:
Example of creating a table Syntax: CREATE TABLE table_name ( column_name1 data_type(size), column_name2 data_type(size), column_name3 data_type(size), .... );
What is the LIKE Operator used for?
The LIKE operator is used to search for a specified pattern in a column.
Does the NOT NULL Constraint always needs to contain a value?
Yes, The NOT NULL constraint enforces a field to always contain a value.
Example of UNION syntax:
Example of UNION syntax: SELECT column_name(s) FROM table1 UNION SELECT column_name(s) FROM table2;
Example of a SQL Constrain syntax:
Example of a SQL Constrain syntax: CREATE TABLE table_name ( column_name1 data_type(size) constraint_name, column_name2 data_type(size) constraint_name, column_name3 data_type(size) constraint_name, .... );
What does the SELECT INTO do?
The SELECT INTO statement selects data from one table and inserts it into a new table.
Can SQL Constrains be specified when a table is Created?
Yes, Constraints can be specified when the table is created (inside the CREATE TABLE statement) or after the table is created (inside the ALTER TABLE statement).
Is the SELECT TOP supported by all database systems?
No, Not all database systems support the SELECT TOP clause.
Example of UNIQUE Constrain Syntax:
Example of UNIQUE Constrain Syntax: CREATE TABLE Persons ( P_Id int NOT NULL UNIQUE, LastName varchar(255) NOT NULL, FirstName varchar(255), Address varchar(255), City varchar(255) )
What are the Aliases (AS) main purpose?
Readability - Basically, aliases are created to make column names more readable.
What is the INNER JOIN keyword do?
The INNER JOIN keyword selects all rows from both tables as long as there is a match between the columns in both tables.
What is the JOIN clause used for?
An SQL JOIN clause is used to combine rows from two or more tables, based on a common field between them.
Example of LIKE operator syntax
LIKE operator syntax example: SELECT column_name(s) FROM table_name WHERE column_name IN (value1,value2,...); SELECT * FROM Customers WHERE City IN ('Paris','London');
Example of SELECT INTO syntax:
Example of SELECT INTO syntax: SELECT * INTO newtable [IN externaldb] FROM table1; SELECT column_name(s) INTO newtable [IN externaldb] FROM table1;
What does the NOT NULL Constraint do?
The NOT NULL constraint enforces a column to NOT accept NULL values.
What happens on a SQL constrain if there is a violation between the constrain and the data action?
If there is any violation between the constraint and the data action, the action is aborted by the constraint.
What does the INSERT INTO do?
The INSERT INTO SELECT statement selects data from one table and inserts it into an existing table.
What does the RIGHT JOIN do?
The RIGHT JOIN keyword returns all rows from the right table (table2), with the matching rows in the left table (table1).
What does the FULL OUTER JOIN keyword return?
The FULL OUTER JOIN keyword returns all rows from the left table (table1) and from the right table (table2).
What is the CREATE TABLE statement used for?
The CREATE TABLE statement is used to create a table in a database.
Can you INSERT / UPDATE a new record on a NOT NULL without adding a value to this field?
No, this is the whole point of NOT NULL, This means that you cannot insert a new record, or update a record without adding a value to this field.
What is the CREATE DATABASE statement used for?
The CREATE DATABASE statement is used to create a database.
Example of Aliases (AS) syntax:
Example of Aliases (AS) syntax: SELECT column_name AS alias_name FROM table_name; SELECT column_name(s) FROM table_name AS alias_name;
Example of LEFT JOIN syntax:
Example of LEFT JOIN syntax: SELECT column_name(s) FROM table1 LEFT JOIN table2 ON table1.column_name=table2.column_name;
What is the BETWEEN operator do?
The BETWEEN operator selects values within a range.
Example of RIGHT JOIN syntax:
Example of RIGHT JOIN syntax: SELECT column_name(s) FROM table1 RIGHT JOIN table2 ON table1.column_name=table2.column_name;
What does the UNIQUE Constraint do?
The UNIQUE constraint uniquely identifies each record in a database table.
In an INSERT INTO are all rows affected?
No, Any existing rows in the target table are unaffected.
Example of NOT NULL Syntax:
Example of NOT NULL Syntax: CREATE TABLE PersonsNotNull ( P_Id int NOT NULL, LastName varchar(255) NOT NULL, FirstName varchar(255), Address varchar(255), City varchar(255) )
Besides UNION needing to have the same number of columns is there anything else that needs to be similar?
Data TYPES, and Order Yes, The columns must also have similar data types. Also, the columns in each SELECT statement must be in the same order.
Example of BETWEEN operator syntax:
BETWEEN operator syntax: SELECT column_name(s) FROM table_name WHERE column_name BETWEEN value1 AND value2;
What does a UNIQUE Constraint provide?
Uniqueness - The UNIQUE and PRIMARY KEY constraints both provide a guarantee for uniqueness for a column or set of columns.
What are the values that BETWEEN operator can handle?
Numbers, Text, or Dates. The values handled by the BETWEEN operator can be numbers, text, or dates.
Example of FULL OUTER JOIN syntax:
Example of FULL OUTER JOIN syntax: SELECT column_name(s) FROM table1 FULL OUTER JOIN table2 ON table1.column_name=table2.column_name;
Does the UNION operator needs to have the same number of columns?
Yes, the UNION operator needs to have the same number of columns. Notice that each SELECT statement within the UNION must have the same number of columns.
Example of CREATE DATABASE syntax:
Example of CREATE DATABASE syntax: CREATE DATABASE dbname;
Section 3
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Data Type: Float
Approximate numerical, mantissa precision 16 float
What does the AUTO INCREMENT used for?
Auto-increment allows a unique number to be generated when a new record is inserted into a table.
Why would we use the AUTO INCREMENT?
Automatically create the value of Primary Key Very often we would like the value of the primary key field to be created automatically every time a new record is inserted.
How is the type TIMESTAMP in SQL structured?
The type TIMESTAMP is formatted like: A Unique Number
Data Type: Variable Character
Character string. Variable length. Maximum length n varchar(64)
Example of NULL syntax:
Example of NULL syntax: SELECT LastName,FirstName,Address FROM Persons WHERE Address IS NULL SELECT LastName,FirstName,Address FROM Persons WHERE Address IS NOT NULL
What is a View?
A view is a virtual table based on the result-set of an SQL statement
Is the update time of a table with indexes the same as the update time without indexes?
No, the update time is not the same, Updating a table with indexes takes more time than updating a table without (because the indexes also need an update).
What does a VIEW contain?
A view contains rows and columns, just like a real table.
What happens if you define a CHECK constraint on a table?
If you define a CHECK constraint on a table it can limit the values in certain columns based on values in other columns in the row.
Can a PRIMARY KEY contain NULL VALUES?
No, A primary key column cannot contain NULL values.
What is the DROP statement used for?
Indexes, tables, and databases can easily be deleted/removed with the DROP statement.
Example of DROP VIEW syntax:
Example of DROP VIEW syntax: DROP VIEW view_name
What are the INDEXES used for?
Indexes allow the database application to find data fast; without reading the whole table.
How is the type DATE in SQL structured?
The type DATE is formatted like: YYYY-MM-DD
Example of CREATE INDEX syntax:
Example of CREATE INDEX syntax: CREATE INDEX index_name ON table_name (column_name)
Can you add SQL functions to a view?
Yes, You can add SQL functions, WHERE, and JOIN statements to a view and present the data as if the data were coming from one single table.
Should most tables contain a Primary Key?
Yes, Most tables should have a primary key, and each table can have only ONE primary key.
So if there is a delay on updating a table with index when should we used indexes?
You should only create indexes on columns (and tables) that will be frequently searched against.
What are the FIELDS in a view?
The fields in a view are fields from one or more real tables in the database.
Example of a FOREIGN KEY Syntax
Example of a FOREIGN KEY Syntax CREATE TABLE Orders ( O_Id int NOT NULL, OrderNo int NOT NULL, P_Id int, PRIMARY KEY (O_Id), FOREIGN KEY (P_Id) REFERENCES Persons(P_Id) )
What is the CREAT INDEX used for?
The CREATE INDEX statement is used to create indexes in tables.
CHECK Constrain on a Single Column:
If you define a CHECK constraint on a single column it allows only certain values for this column.
Example of AUTO INCREMENT syntax:
Example of AUTO INCREMENT syntax: CREATE TABLE Persons ( ID int IDENTITY(1,1) PRIMARY KEY, LastName varchar(255) NOT NULL, FirstName varchar(255), Address varchar(255), City varchar(255) )
What are the types of Data types for storing a date or a date / time value in a database?
There are some types for storing a date or date / time value in the database: DATE - format YYYY-MM-DD DATETIME - format: YYYY-MM-DD HH:MI:SS SMALLDATETIME - format: YYYY-MM-DD HH:MI:SS TIMESTAMP - format: a unique number
Where will the DEFAULT constrain add the values?
The default value will be added to all new records, if no other value is specified.
Data Type: Boolean
Stores TRUE or FALSE values boolean
Do PRIMARY KEYS must contain UNIQUE values?
Yes, Primary keys must contain UNIQUE values.
Example of DROP Syntax:
Example of DROP Syntax: DROP INDEX table_name.index_name DROP DATABASE database_name
Example of a CREATE VIEW syntax:
Example of a CREATE VIEW syntax: CREATE VIEW view_name AS SELECT column_name(s) FROM table_name WHERE condition
What is the ALTER statement used for?
The ALTER TABLE statement is used to add, delete, or modify columns in an existing table.
Data Type: Decimal
Exact numerical, precision p, scale s. Example: decimal(5,2) is a number that has 3 digits before the decimal and 2 digits after the decimal. decimal(6,2)
Data Type: Integer
Integer numerical (no decimal). Precision p int
What does the PRIMARY KEY do?
The PRIMARY KEY constraint uniquely identifies each record in a database table.
What is the most difficult part of working with SQL dates?
The most difficult part when working with dates is to be sure that the format of the date you are trying to insert, matches the format of the date column in the database.
Data Type: Character
Character string. Fixed-length n char(32)
What if a column in a table is Optional?
If a column in a table is optional, we can insert a new record or update an existing record without adding a value to this column. This means that the field will be saved with a NULL value.
How would you remove a column in a table with ALTER?
To remove a column in a table, use the following syntax: ALTER TABLE table_name DROP COLUMN column_name
Example of CHECK constraint Syntax:
Example of CHECK constraint Syntax: CREATE TABLE Persons ( P_Id int NOT NULL CHECK (P_Id>0), LastName varchar(255) NOT NULL, FirstName varchar(255), Address varchar(255), City varchar(255) )
How would you add a column in a table with ALTER?
To add a column in a table, use the following syntax: ALTER TABLE table_name ADD column_name datatype
Example of DEFAULT constraint syntax:
Example of DEFAULT constraint syntax: CREATE TABLE Persons ( P_Id int NOT NULL, LastName varchar(255) NOT NULL, FirstName varchar(255), Address varchar(255), City varchar(255) DEFAULT 'Sandnes' );
How is the type DATETIME in SQL structured?
The type DATETIME is formatted like: YYYY-MM-DD HH:MI:SS
What is the DEFAULT Constraint used for?
The DEFAULT constraint is used to insert a default value into a column.
What is a FOREIGN KEY?
A FOREIGN KEY in one table points to a PRIMARY KEY in another table.
What do Null Values represent?
NULL values represent missing unknown data. By default, a table column can hold NULL values
How is the type SMALLDATETIME in SQL structured?
The type SMALLDATETIME is formatted like: YYYY-MM-DD HH:MI:SS
Example of UDPATE VIEW syntax:
Example of UDPATE VIEW syntax: CREATE OR REPLACE VIEW view_name AS SELECT column_name(s) FROM table_name WHERE condition
Example of a PRIMARY KEY syntax:
Example of a PRIMARY KEY syntax: CREATE TABLE Persons ( P_Id int NOT NULL PRIMARY KEY, LastName varchar(255) NOT NULL, FirstName varchar(255), Address varchar(255), City varchar(255) )
What is the CHECK Constraint used for?
The CHECK constraint is used to limit the value range that can be placed in a column.
Does SQL Dates come already with some predefined types for defining and storing a date or a date / time value?
Yes, there are some already predefined date types.
Section 4
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What does an Average Function return?
The AVG() function returns the average value of a numeric column.
Example of MAX Function Syntax:
Example of MAX Function Syntax: SELECT MAX(column_name) FROM table_name;
What does a Count Function Return?
The COUNT() function returns the number of rows that matches a specified criteria.
Data Type: Date
Stores year, month, and day values date
Example of a COUNT function syntax:
Example of a COUNT function syntax: SELECT COUNT(column_name) FROM table_name;
Example of a Subquery Syntax
Example of a Subquery Syntax SELECT a.studentid, a.name, b.total_marks FROM student a, marks b WHERE a.studentid = b.studentid AND b.total_marks > (SELECT total_marks FROM marks WHERE studentid = 'V002');
SQL Functions
SQL has many built-in functions for performing calculations on data. Aggregate functions and Scalar Functions.
Example of Round Function Syntax:
Example of Round Function Syntax: SELECT ROUND(column_name,decimals) FROM table_name;
Can you have multiple Schemas in a Database?
Yes, You may have one or multiple schemas in a database.
Example of HAVING Function Syntax:
Example of HAVING Function Syntax: SELECT column_name, aggregate_function(column_name) FROM table_name WHERE column_name operator value GROUP BY column_name HAVING aggregate_function(column_name) operator value;
What does the Lower Case Function do?
The LCASE() function converts the value of a field to lowercase.
Data Type: Binary Object
Binary string. Fixed-length n Syntax: Blob Text Fixed Length Syntax: Binary (fixed up to 8K) Varbinary (<8K) Image (<2GB)
What does limit the user access to the Database?
The user access is limited by the user's privileges within the database, the user has control over objects that are created, manipulated, and deleted.
Does a Schema has a limit to the number of objects it may contain?
No, unless it's restricted by implementation, Schema does not have a limit to it's containing objects. A schema can consist of a single table and has no limits to the number of objects that it may contain, unless restricted by a specific database implementation.
Example of MIN function Syntax:
Example of MIN function Syntax: SELECT MIN(column_name) FROM table_name;
Why was the HAVING Function added to SQL?
The HAVING clause was added to SQL because the WHERE keyword could not be used with aggregate functions.
When do you want to use an Intersect?
Use an Intersect to return only values that are in the first query AND also in the second query.
Example of Length syntax
Example of Length syntax SELECT LENGTH(column_name) FROM table_name;
When a user creates an Object did he just created his own Schema?
Yes, Basically, any user who creates an object has just created his or her own schema.
What does the Upper Case Function do?
The UCASE() function converts the value of a field to uppercase.
In a Schema what is a Database Username
This username is called the schema owner, or the owner of the related group of objects.
Data Type: Time
Stores hour, minute, and second values time
Data Type: Timestampe
Stores year, month, day, hour, minute, and second values timestamp
What does a COUNT(column_name) function Return?
The COUNT(column_name) function returns the number of values (NULL values will not be counted) of the specified column
Example of Now Function Syntax
Example of Now Function Syntax SELECT NOW() FROM table_name;
Example of First Function Syntax:
Example of First Function Syntax: SELECT FIRST(column_name) FROM table_name;
What is the Length Function used for?
The LEN() function returns the length of the value in a text field.
Example of GROUP by Function Syntax:
Example of GROUP by Function Syntax: SELECT column_name, aggregate_function(column_name) FROM table_name WHERE column_name operator value GROUP BY column_name;
Example of mid Syntax:
Example of mid Syntax: SELECT MID(column_name,start,length) AS some_name FROM table_name;
What does the Now Function return?
The NOW() function returns the current system date and time.
What is a Schema?
A schema is a collection of database objects (tables) associated with one particular database username.
Where is the Group By Function used?
The GROUP BY statement is used in conjunction with the aggregate functions to group the result-set by one or more columns.
What is the Format Function used for?
The FORMAT() function is used to format how a field is to be displayed. SELECT FORMAT(column_name,format) FROM table_name;
What is the Round Function used for?
The ROUND() function is used to round a numeric field to the number of decimals specified.
What does the Last Function Return?
The LAST() function returns the last value of the selected column. Only in MS Access
What does the Max Function Return?
The MAX() function returns the largest value of the selected column.
Data Type: Aray
A set-length and ordered collection of elements
Example of LAST Function Syntax
Example of LAST Function Syntax SELECT LAST(column_name) FROM table_name;
What does the Sum Function Return?
The SUM() function returns the SUM of the values of the selected column.
Example of UCASE Function Syntax:
Example of UCASE Function Syntax: SELECT UPPER(column_name) FROM table_name;
What is a Subquery?
A subquery is a SQL query nested inside a larger query.
What is the Mid Function used for?
The MID() function is used to extract characters from a text field.
Example of LCASE syntax:
Example of LCASE syntax: SELECT LOWER(column_name) FROM table_name;
What does the Min Function Return?
The MIN() function returns the smallest value of the selected column.
What is a Intersect?
A Intersect is the Same as INNER JOIN
Example of Sum Function Syntax:
Example of Sum Function Syntax: SELECT MIN(column_name) FROM table_name;
What does the First Function Return?
The FIRST() function returns the first value of the selected column. Only in MS Access
Data Type: Real
Approximate numerical, mantissa precision 7 real
Example of an Average Function Syntax:
Example of an Average Function Syntax: SELECT AVG(column_name) FROM table_name
How is the Round Function processed? is there any rule to be aware of?
IEEE 754, Many database systems have adopted the IEEE 754 standard for arithmetic operations, according to which the default rounding behavior is "round half to even." In this scheme, .5 is rounded to the nearest even integer. So, both 11.5 and 12.5 would be rounded to 12.
Section 5
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What is a Data type: varchar(size)
Variable-length character string. Max size is specified in parenthesis.
What does the SIGN(x) return?
Returns the sign of input x as -1,0,1
Can you use an > greater than as a conditional selection for the SELECT clause?
Yes, you can use an > greater than as a conditional selection for the SELECT clause
What is Data type: char(size)
It's the Fixed-length character string. Size specified in parentheses. 255
What does the CEILING(x), CEIL(x) return?
Returns the smallest integer value that is greater than or equal to x
Can you use an = equal as a conditional selection for the SELECT clause?
Yes, you can use an = equal as a conditional selection for the SELECT clause
What does a FULL JOIN return?
A FULL JOIN Returns all rows for which there is a match in EITHER of the tables.
What is a Data type: number(size)
Number value with a max number of column digits specified in parenthesis.
What does the POWER(x,y) return?
Returns the value of x raised to the power of y
What does the MIN Return?
Returns the smallest value in a given column
What does a CROSS JOIN return?
A CROSS JOIN returns all records where each row from the first table is combined with each row from the second table (i.e., returns the Cartesian product of the sets of rows from the joined tables).
Example of a SELECT statement syntax
Example of a SELECT statement syntax select "column1" [,"column2",etc] from "tablename" [where "condition"]; [] = optional
What does a RIGHT JOIN Return?
A RIGHT JOIN Returns all rows from the right table, and the matched rows from the left table. This is the exact opposite of a LEFT JOIN;
Example of an INSERT INTO statement
Example of an INSERT INTO statement insert into "tablename" (first_column,...last_column) values (first_value,...last_value);
Mathematical Functions
Mathematical Functions Include: +, -, *, /, %
What will be the results of a RIGHT JOIN
The results of a RIGHT JOIN will contain all records from the right table, even if the JOIN condition doesn't find any matching records in the left table.
Can you use an >= greater or equal than as a conditional selection for the SELECT clause?
Yes, you can use an >= greater or equal than as a conditional selection for the SELECT clause
What will be the result of a LEFT JOIN if the ON clause doesn't match any records in the right table?
If the ON clause doesn't match any records in the right table, the LEFT JOIN will still return a row in the result for that record in the left table, but with NULL in each column from the right table.
What is the result of a FULL JOIN?
The result of a FULL JOIN is equivalent to performing a UNION of the results of left and right outer queries. ex: Produces the set of all records in Table A and Table B, with matching records from both sides if available. If no match, missing side will contain null.
Can you use an <> not equal as a conditional selection for the SELECT clause?
Yes, you can use an <> not equal as a conditional selection for the SELECT clause
What is the DELETE statement used for?
The DELETE statement is used to delete records or rows from the table
Is a FULL JOIN the same as FULL OUTER JOIN?
Yes, a FULL JOIN is the same as FULL OUTER JOIN
Can you use an LIKE as a conditional selection for the SELECT clause?
Yes, you can use an LIKE as a conditional selection for the SELECT clause
Could you say that a FULL JOIN is a combination of the LEFT AND RIGHT JOIN?
Yes, Conceptually, a FULL JOIN combines the effect of applying both a LEFT JOIN and a RIGHT JOIN;
Describe an Inner Join
A inner join is a simple join that returns all rows for which there is at least one match in BOTH tables.
What does the ABS(x) return?
Returns the absolute value of x
What is the difference between UNION and UNION ALL?
The difference between UNION and UNION ALL is that UNION will omit duplicate records whereas UNION ALL will include duplicate records.
Conditional selections used in the where clause for SELECT
= Equal > Greater than < Less than >= Greater than or equal <= Less than or equal <> Not equal to LIKE
Is a LEFT JOIN the same as LEFT OUTER JOIN?
Yes, a left join can also be referred as a left outer join
What does the FLOOR(x) return?
Returns the largest integer value that is less than or equal to x
What does the MAX Return?
Returns the largest value in a given column
What does the MOD(x,y) return?
Modulo- returns the integer remainder of x divided by y (same as x%y)
Is there more than one way to specify a CROSS JOIN?
Yes, a CROSS JOIN can either be specified using the CROSS JOIN syntax ("explicit join notation") or (b) listing the tables in the FROM clause separated by commas without using a WHERE clause to supply join criteria ("implicit join notation").
Example of a JOIN syntax
If you have a Table A and a Table B SELECT * FROM TableA INNER JOIN TableB ON TableA."col" = TableB."col" produces only the set of records that match in both A and B
Data type: number (size,d)
Number value with a maximum number of digits of "size" total, with a max number of "d" digits to the right of the decimal.
What does the ROUND(x) return?
Returns the value of x rounded to the nearest whole integer
What will the RIGHT JOIN give if the ON clause doesn't match any records in the left table?
If the ON clause doesn't match any records in the left table, the RIGHT JOIN will still return a row in the result for that record in the right table, but with NULL in each column from the left table.
Can you use an < less than as a conditional selection for the SELECT clause?
Yes, you can use an < less than as a conditional selection for the SELECT clause
What is the default type of join if no specific JOIN type is specified?
Inner Join, This is the default type of join if no specific JOIN type is specified.
What are the different types of JOIN clauses supported by the ANSI- standard?
(1) Inner Join (2) Left Join (3) Right Join (4) Full Join (5) Cross Join
COUNT- Aggregate fxn
Returns the total number of values in a given column
Example of HAVING clause, GROUP BY syntax
Example of HAVING clause, GROUP BY syntax SELECT column1, SUM(column2) FROM "list-of-tables" GROUP BY "column-list" HAVING "condition";
What does a LEFT JOIN return?
A left join returns all rows from the left table, and the matched rows from the right table;
What is the SELECT Statement (def, partial) used for?
The SELECT statement is used to query the database and retrieve.
What will be the results of a LEFT JOIN?
the results of a LEFT JOIN, will contain all records from the left table, even if the JOIN condition doesn't find any matching records in the right table.
HAVING clause, GROUP BY
Allows you to specify conditions on the rows for each group- in other words, which rows should be selected will be based on the conditions you specify needs to follow GROUP BY clause
Can you use an <= less than as a conditional selection for the SELECT clause?
Yes, you can use an <= less than as a conditional selection for the SELECT clause
COUNT(*) - Aggregate fxn
Returns the number of rows in a table
What does UNION do?
UNION merges the contents of two structurally-compatible tables into a single combined table.
Is a RIGHT JOIN the same as RIGHT OUTER JOIN?
Yes, A RIGHT JOIN is the same as RIGHT OUTER JOIN
Section 6
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