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 FROM 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:
SELECT column_name,column_name
FROM table_name;
Example:
...
INSERT INTO statements
INSERT INTO statements insert a new record into a database table.
The INSERT INTO statement has two forms:
- Specify values, do not specify columns
- Specify values and columns
Syntax (first form):
INSERT INTO table_name
VALUES (value1,value2,value3,...);
Syntax (second form):
INSERT INTO table_name (column1,column2,column3,...)
VALUES (value1,value2,value3,...);
Example:
INSERT INTO J_Error_Prod (Fk_Error, Fk_Prod) VALUES (99, 999)
UPDATE statements
UPDATE statements update zero or more existing records in a database table.
Syntax:
UPDATE table_name
SET column1=value1,column2=value2,...
WHERE some_column=some_value;
Example:
...
If the WHERE clause is omitted, the UPDATE query will update all records in the specified table.
DELETE FROM statements
DELETE FROM 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:
DELETE FROM J_Error_Prod WHERE Fk_Error = 99 AND Fk_Prod = 999
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.
See also
External links
- SQL SELECT @ W3Schools
- SQL INSERT INTO @ W3Schools
- SQL UPDATE @ W3Schools
- SQL DELETE @ W3Schools
