MacLochlainns Weblog

MySQL membership conditions are in the MySQL 8 Documentation. They’re found in the 13.2.11.3 Subqueries with ANY, IN, or SOME section. The IN and =ANY operators both perform equality matches with one twist. The IN operator works with a set of values or a subquery but the =ANY operator only works with a subquery.

I created the digits, letters, and words tables for this example. They hold the following values respectively:

• The numbers table holds the values of 1, 2, 3, and 4
• The letters table holds the values of 'a', 'b', 'c', and 'd'
• The words table holds the values of 'Captain America', 'Iron Man', 'Thor', and Ant-Man

The following examples show the IN and =ANY membership comparison operators:

The IN membership operator:

SELECT 'True Statement' AS result
WHERE  'a' IN ('a','b','c','d');

SELECT 'True Statement' AS result
WHERE  'a' IN (SELECT letter FROM letters);

SELECT 'True Statement' AS result
WHERE   BINARY 'a' IN (SELECT letter FROM letters);

The =ANY membership operator:

SELECT 'True Statement' AS result
WHERE  'a' =ANY ('a','b','c','d');

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''a','b','c','d')' at line 2

The following math operators work with the ANY, SOME, and ALL membership operators:

• >
• >=
• <
• <=
• <>
• !=

While the ANY and SOME membership operators work alike, the AND operator works differently. The ANY and SOME membership operators work like an OR logical operator in the WHERE clause.

For example, the following <ANY comparison works when the right operand is in the set but not the largest element returned by the subquery.

SELECT 'True Statement' AS result
WHERE  2 <SOME (SELECT digit FROM numbers);

You can use a <=ANY or <=SOME when the left operand is equal to the highest digit in the subquery’s result set. The <ALL comparison only works when the left operand is a digit lower than the smallest element returned by the subquery.

SELECT 'True Statement' AS result
WHERE   0 <ALL (SELECT digit FROM numbers);

Here’s a set of SQL commands to setup the test cases for membership operators:

DROP TABLE letters;
CREATE TABLE letters (letter VARCHAR(10));
DROP TABLE numbers;
CREATE TABLE numbers (digit int);
DROP TABLE words;
CREATE TABLE words (word VARCHAR(20));
INSERT INTO letters VALUES ('a'),('b'),('c'),('d'),('e');
INSERT INTO numbers VALUES (1),(2),(3),(4),(5);
INSERT INTO words VALUES ('Captain America'),('Thor'),('Iron Man'),('Ant-Man');

As always, I hope this helps those looking for more examples and good solutions.