如何从select中使用变量来调用存储过程？

Question

我的问题是这段代码。

DELIMITER $$ 

DROP PROCEDURE IF EXISTS agregar_abono$$ 
CREATE PROCEDURE agregar_abono(IN pid_cliente BIGINT, IN pfecha_abono DATE, IN pmonto_abono FLOAT) 
BEGIN 
    DECLARE @idabono BIGINT; 

    -- OTHER CODE ... 

    SELECT id_abono AS idabono FROM abono WHERE fk_cliente = pid_cliente ORDER BY id_abono DESC LIMIT 1; 

    SELECT CONCAT('>', idabono); 


    CALL cobrar_abono(pid_cliente, vid_abono); 

END $$ 

两个SELECT返回的过程：

idabono = 52     --> good! (in the first select) 
CONCAT('>', idabono) = null ---> what?? 

我不知道，因为没有存储在这个变量的结果在存储过程中使用。我使用AS来存储变量。

存储过程调用的标题是：

CREATE PROCEDURE cobrar_abono(IN pid_cliente BIGINT, IN pid_abono BIGINT) 

Answer 1

你在找这个？

... 
DECLARE idabono BIGINT; 
-- OTHER CODE ... 
SET idabono = (SELECT id_abono 
       FROM abono 
       WHERE fk_cliente = pid_cliente 
       ORDER BY id_abono DESC 
       LIMIT 1); 

的SELECT声明本身或许可以

SET idabono = (SELECT MAX(id_abono) 
       FROM abono 
       WHERE fk_cliente = pid_cliente);