SQL statement examples
This article demonstrates a variety of SQL statements.
Contents
Overview
SQL statements, broadly speaking, fall into four commonly used categories:
- SELECT statements return zero or more records
- INSERT INTO statements insert a new record
- UPDATE statements update existing records
- DELETE statements delete existing records
Case insensitivity
SQL statements are typically case-insensitive. These examples follow the common convention of uppercasing SQL keywords.
SELECT statements
SELECT statement return zero or more records.
Syntax:
...
Example:
...
INSERT INTO statements
INSERT INTO statements insert a new record into a database table.
Syntax:
...
Example:
...
UPDATE statements
UPDATE statements update zero or more existing records in a database table.
Syntax:
...
Example:
...
DELETE statements
DELETE statements delete zero or more existing records from a database table.
Syntax:
...
DELETE FROM table_name
WHERE some_column=some_value;
If the WHERE clause is omitted, the DELETE query will delete all records in the specified table.
Example:
...
Different implementations of SQL
Note that different implementations of SQL -- different "flavors" -- may differ in their details. The examples on this page are appropriate to a wide range -- but not necessarily all -- implementations.
External links
- SQL SELECT @ W3Schools
- SQL INSERT INTO @ W3Schools
- SQL UPDATE @ W3Schools
- SQL DELETE @ W3Schools
