mysql 表名作為存儲過程變量

mysql默認不支持表名作為變量名，如下所示

delimiter $$
DROP procedure IF EXISTS getDataByDbName $$ 
CREATE procedure getDataByDbName(in dbName VARCHAR(20))
BEGIN
select * from dbName;
end$$
delimiter;

當運行會報錯

[SQL]
call getDataByDbName("xxx");
[Err] 1146 - Table 'xxx.dbname' doesn't exist

這里需要用到mysql的一個字符串拼接函數CONCAT（），使用用戶變量得到結果，然后輸出即可

delimiter $$
DROP procedure IF EXISTS getDataByDbName $$ 
CREATE procedure getDataByDbName(in dbName VARCHAR(20))
BEGIN
SET @STMT =CONCAT("SELECT * from ",dbName,";"); 
PREPARE STMT FROM @STMT; 
EXECUTE STMT; 
end$$
delimiter;