SQL Where

The SQL WHERE Clause

The WHERE clause is used to filter records.

It is used to extract only those records that fulfill a specified condition.

WHERE Syntax

SQL
SELECT column1, column2, ...
FROM table_name
WHERE condition; 

WHERE Clause Example

The following SQL statement selects all the customers from the country “Mexico”, in the “Customers” table:

SQL
SELECT * FROM Customers
WHERE Country='Mexico'; 

Text Fields vs. Numeric Fields

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

However, numeric fields should not be enclosed in quotes:

SQL
SELECT * FROM Customers
WHERE CustomerID=1; 

Operators in The WHERE Clause

The following operators can be used in the WHERE clause:

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