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SQL

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Date created

Mar 1, 2020

Cards (23)

Section 1

(23 cards)

_

Front

A wildcard character. The _ means you can substitute any individual character here without breaking the pattern. The names Seven and Se7en both match this pattern.

Back

DEFAULT Constraint

Front

DEFAULT columns take an additional argument that will be the assumed value for an inserted row if the new row does not specify a value for that column. ---------------------------------------------------- award_name TEXT DEFAULT 'Grammy'

Back

%

Front

% is a wildcard character that matches zero or more missing letters in the pattern.

Back

Constraints

Front

Constraints add information about how a column can be used. ---------------------------------------------------- CREATE TABLE awards ( id INTEGER PRIMARY KEY, recipient TEXT NOT NULL, award_name TEXT DEFAULT 'Grammy' );

Back

Restrict a query result

Front

WHERE clause filters the result set to only include rows where the following condition is true. You can compare values of two columns in a WHERE clause. ---------------------------------------------------- SELECT x, y FROM coordinates WHERE x > y;

Back

Statement

Front

A statement is a string of characters that the database recognizes as a valid command.

Back

Search for a specific pattern in a column

Front

LIKE is a special operator used with the WHERE clause to search for a specific pattern in a column. LIKE is not case sensitive. ---------------------------------------------------- SELECT * FROM movies WHERE name LIKE 'Se_en';

Back

AS

Front

AS is a keyword in SQL that allows you to rename a column or table using an alias. The new name can be anything you want as long as you put it inside of single quotes. The columns are not renamed in the table. The aliases only appear in the result. ---------------------------------------------------- SELECT name AS 'Titles' FROM movies; SELECT name AS 'title', year AS 'release_year' FROM movies;

Back

Delete a row from a table

Front

DELETE FROM table WHERE column condition;

Back

Table

Front

A table is a collection of data organized into rows and columns.

Back

Add rows to an existing table

Front

INSERT INTO table (col1, col2, col3) VALUES (row1_val1, row1_val2, row1_val3), (row2_val1, row2_val2, row2_val3), (row3_val1, row3_val2, row3_val3);

Back

UNIQUE Constraint

Front

UNIQUE columns have a different value for every row. This is similar to PRIMARY KEY except a table can have many different UNIQUE columns. ---------------------------------------------------- recipient TEXT UNIQUE

Back

Comparison operators used with the WHERE

Front

= equal to != not equal to > greater than < less than >= greater than or equal to <= less than or equal to

Back

Add a new column to an existing table

Front

ALTER TABLE table ADD COLUMN column data_type;

Back

DISTINCT

Front

DISTINCT is used to return unique values in the output. It filters out all duplicate values in the specified column(s). The DISTINCT clause can only be used once in the query and will apply only to the column immediately after it. ---------------------------------------------------- SELECT DISTINCT tools FROM inventory;

Back

null

Front

A special value in SQL that represents missing or unknown data.

Back

Edit a row in a table

Front

UPDATE table SET column = data

Back

PRIMARY KEY Constraint

Front

PRIMARY KEY columns can be used to uniquely identify the row. Attempts to insert a row with an identical value to a row already in the table will result in a constraint violation which will not allow you to insert the new row. ---------------------------------------------------- id INTEGER PRIMARY KEY

Back

Conditional clause to check if a value is null

Front

IS NULL

Back

Relational Database

Front

A relational database is a database that organizes information into one or more tables.

Back

Queries

Front

Queries allow us to communicate with the database by asking questions and having the result set return data relevant to the question.

Back

NOT NULL Constraint

Front

NOT NULL columns must have a value. Attempts to insert a row without a value for a NOT NULL column will result in a constraint violation and the new row will not be inserted. ---------------------------------------------------- recipient TEXT NOT NULL

Back

Make a new table

Front

CREATE TABLE table_name ( column_1 data_type, column_2 data_type, column_3 data_type );

Back