How to use and in mysql

The AND operator in MySQL connects Boolean expressions and returns true if and only if all expressions are true, otherwise it returns false. It is used to narrow query results, find records that meet multiple criteria, or exclude records that do not meet criteria.

Usage of AND in MySQL

The AND operator in MySQL is used to connect two or more Boolean An expression that produces a result that returns TRUE or FALSE. The result is TRUE if and only if all connected expressions are TRUE. Otherwise, the result is FALSE.

Syntax

<code>表达式1 AND 表达式2 ...</code>

Example

<code>SELECT * FROM users
WHERE age > 18 AND gender = 'male';</code>

This query will retrieve all user records that are older than 18 years old and whose gender is male .

Priority

The AND operator has lower precedence than the OR operator and higher than the NOT operator.

Truth table

Expression 1	Expression 2	Result
TRUE	TRUE	TRUE
TRUE	FALSE	FALSE
FALSE	TRUE	FALSE
FALSE	FALSE	FALSE

Usage scenarios

AND operator is usually used to narrow the query result. For example:

• Find records that meet multiple conditions.
• Concatenate multiple Boolean expressions to create more complex queries.
• Exclude records that do not meet specific conditions.

Note

• Avoid using AND NULL in an expression because it always returns NULL.
• Multiple AND operators can be combined together to create more complex conditions.
• Use parentheses to control the precedence of operators.

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