SQL WHERE Clause
The WHERE clause is used to filter records that fulfill a specified condition.
WHERE Syntax
SELECT column1, column2, ...
FROM table_name
WHERE condition;
Note:
The WHERE clause is not only used in SELECT statements, it is also used in UPDATE, DELETE, etc.
Demo Database
Below is a selection from the "Customers" table:
| CustomerID | CustomerName | ContactName | City | PostalCode | Country |
|---|---|---|---|---|---|
| 1 | Alfreds Futterkiste | Maria Anders | Berlin | 12209 | Germany |
| 2 | Ana Trujillo Emparedados | Ana Trujillo | México D.F. | 05021 | Mexico |
| 3 | Antonio Moreno Taquería | Antonio Moreno | México D.F. | 05023 | Mexico |
| 4 | Around the Horn | Thomas Hardy | London | WA1 1DP | UK |
| 5 | Berglunds snabbköp | Christina Berglund | Luleå | S-958 22 | Sweden |
WHERE Clause Example
The following SQL statement selects all the customers from "Mexico":
Example
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:
Example
SELECT * FROM Customers
WHERE CustomerID = 1;
Operators in 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 (also != in some versions) |
BETWEEN |
Between a certain range |
LIKE |
Search for a pattern |
IN |
To specify multiple possible values for a column |
Try It Yourself
Tip:
You can combine multiple conditions using AND and OR operators, which we'll learn in the next tutorial.