Where (SQL)

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A WHERE statement in SQL specifies that a SQL command should only be run on rows that meet a specified condition. WHERE statements are not typically required, but should be used if you only want a certain portion of your data to be affected by your SQL Statement.

The WHERE statement has the following form:

COMMAND FROM table_name WHERE condition

Any rows meeting the WHERE condition will have the specified SQL command performed on it.

[edit] Examples:

Uses the DELETE command to remove rows in mytable, if the value of mycol is greater than 100.

DELETE FROM mytable WHERE mycol > 100;

Without the WHERE statement, it delete all rows from mytable:

DELETE FROM mytable;

Multiple conditions: Deletes rows in mytable if the value of mycol is greater than 100, and if item is less than specific

DELETE FROM mytable WHERE mycol > 100 AND item < specific;