SQL WHERE Keyword

SELECT

The WHERE command filters a result set to include only records that fulfill a specified condition.

The following SQL statement selects all the customers from "Mexico" in the "Customers" table:

SELECT * FROM Customers
WHERE Country='Mexico';

SQL requires single quotes around text values (most database systems will also allow double quotes).

However, numeric fields should not be enclosed in quotes:

SELECT * FROM Customers
WHERE CustomerID=1;

Note: The WHERE clause is not only used in SELECT statement, it is also used in UPDATE, DELETE statement, etc.!

The following operators can be used in the WHERE clause:

Operator	Description
=	Equal
<>	Not equal. Note: In some versions of SQL this operator may be written as !=
>	Greater than
<	Less than
>=	Greater than or equal
<=	Less than or equal
BETWEEN	Between a certain range
LIKE	Search for a pattern
IN	To specify multiple possible values for a column