Question

mysql存储过程传多个参数，但并不是所有参数全输入，这要怎么写，

不输入的时候默认为空，然后判断为空的时候，最后有一个select语句对传入参数进行查询，执行的时候参数怎么输入？
BEGIN
#Routine body goes here...
SELECT * FROM computer_prod WHERE CPU_numb=IFNULL(cpuNumb,TRUE) AND hard_disk_capacity=IFNULL(hardDiskCapacity,TRUE) AND memory_capacity=IFNULL(memoryCapacity,TRUE) AND CPU_freq=IFNULL(cpuFreq,TRUE)
And memory_clock=IFNULL(memoryClock,TRUE) AND memory_interface=IFNULL(memoryInterface,TRUE);
END

Answer 1

mysql> DELIMITER //
mysql> CREATE PROCEDURE HelloWorld2(
-> IN vUserName VARCHAR(10),
-> OUT vOutValue VARCHAR(10),
-> INOUT vInOutValue VARCHAR(10))
-> BEGIN
-> SELECT CONCAT('Hello ', vUserName);
-> SET vOutValue = 'A';
-> SET vInOutValue = 'B';
-> END//
Query OK, 0 rows affected (0.00 sec)

mysql> call HelloWorld2('Edward', @a, @b)//
+-----------------------------+
| CONCAT('Hello ', vUserName) |