Custom function for DDL operation example of MySQL database

This article mainly introduces the custom function of the MySQL database DDL operation example, the content of the article is carefully selected and edited by the author, it has a certain pertinence, and it is of great significance to everyone's reference, the following is to understand the custom function of the MySQL database DDL operation example with the author.

1. Background

* Custom functions are very similar to stored procedures, but must have a return value.

two。 Custom function example [factorial]

* create a custom function func_factorial

Delimiter sets statement Terminator

Mysql > delimiter / / mysql > CREATE FUNCTION func_factorial (total INT)-> RETURNS INT-> BEGIN-> DECLARE i INT;-> DECLARE res INT;-> SET I = 1;-> SET res = 1;-> IF total SET total = 1;-> END IF;-> WHILE i SET res = res * I;-> SET I = I + 1 -> END WHILE;-> RETURN res;-> END; / / Query OK, 0 rows affected (0.01 sec) mysql > delimiter

* call the custom function func_factorial

Mysql > SELECT func_factorial (10); +-+ | func_factorial (10) | +-+ | 3628800 | +-+ 1 row in set (0.01sec)

3. Summary

In order to demand-driven technology, there is no difference in technology itself, only in business.

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