乘以Select MySQL 5.6

Question

我想在MySQL 5.6中創建函數。該功能將通過計數玩家乘以參數。但我不知道我該怎麼做。

我覺得這樣，但它沒有按預期工作。

DROP FUNCTION IF EXISTS do_it; 

DELIMITER $$ 
CREATE FUNCTION do_it (s INT) RETURNS INT DETERMINISTIC 
    BEGIN 
    DECLARE k INT; 
    SELECT COUNT(id_player) as allPlayers FROM players; 
    SET k= allPlayers * s; 
    RETURN k; 
    END$$ 
DELIMITER ; 

SELECT do_it(2); 

Answer 1

而是做這樣的方式

DECLARE k INT; 
declare multiplyvar int; 
SELECT COUNT(id_player) into multiplyvar FROM players; 
SET k = multiplyvar * s; 
RETURN k;