Usage of any and all in mysql

In MySQL, ANY and ALL check whether at least one record or all records in the subquery meet the conditions. ANY is suitable for determining existence, while ALL is suitable for verifying consistency. The difference is that ANY only needs to find one record that meets the condition to return true, while ALL requires all records to meet the condition.

Usage of ANY and ALL in MySQL

Concept definition

• ANY: Check that at least one record in the subquery meets the specified condition.
• ALL: Check that all records in the subquery meet the specified conditions.

Syntax

ANY(subquery)
ALL(subquery)

Where subquery is a subquery that returns a Boolean value.

Usage

ANY

• Check whether there are records that meet the conditions in the subquery.
• Returns 1 (true) if a matching record is found, otherwise returns 0 (false).
• Commonly used to determine whether a specific element exists in a collection.

Example:

<code>SELECT CASE
  WHEN ANY(SELECT 1 FROM orders WHERE product_id = 123)
  THEN 'Product exists'
  ELSE 'Product does not exist'
END;</code>

ALL

• Check that all records in the subquery satisfy the condition .
• Returns 1 (true) if all records meet the conditions, otherwise returns 0 (false).
• Commonly used to ensure that all elements in a collection meet certain criteria.

Example:

<code>SELECT CASE
  WHEN ALL(SELECT price FROM orders WHERE product_id = 123) > 50
  THEN 'All products are expensive'
  ELSE 'Some products are not expensive'
END;</code>

DIFFERENCE

• ANY Just find one Records that meet the conditions will return true, while ALL requires all records to meet the conditions before returning true.
• ANY is often used to check for existence, while ALL is often used to verify consistency.

Note

• The subquery must return a boolean value (true/false).
• An empty subquery will result in NULL results.
• When using ALL and ANY, you should be aware of the performance impact of subqueries.

The above is the detailed content of Usage of any and all in mysql. For more information, please follow other related articles on the PHP Chinese website!