By default, a SQL query retrieves every row in your dataset. Use the optional WHERE clause to restrict your query results to a conditional expression.
The conditional expression in the WHERE clause takes the following syntax.
fieldExpression [logicalOperator fieldExpression2][...]
SELECT COUNT(*) as Count
FROM "Superstore"
WHERE City = 'San Francisco';
| Count |
|---|
| 510 |
You can add multiple field expressions to conditional expressions with logical operators.
SELECT COUNT(*) as Count FROM "Superstore"
WHERE City = 'Los Angeles' OR City = 'San Francisco';
| Count |
|---|
| 1,257 |
The WHERE clause supports these operators.
| Type | Operator Name | Supported Types |
|---|---|---|
| Comparison Operators | !=, = | Numeric, String, Boolean |
| <, <=, >, >= | Numeric, String | |
IN, NOT IN |
Numeric, String | |
| Null Operators | IS NULL, IS NOT NULL |
Numeric |
| Logical Operators | AND, OR, NOT |
Boolean |
The left operand of a comparison operator must be a valid field. The right operand cannot be a field. Arithmetic operators (e.g. +, -, /, *, %) between supported types can be used on the right hand side.
WHERE is limited to comparisons within a single column.
In a non-nested query (a non-subquery), you can’t pass fields to a math or string function in a WHERE clause. You can pass a constant. To pass fields to a math or string function in a subquery, include it in the outer query’s WHERE clause. If you use it in the innermost query, SQL throws an error.