如何从MySQL表返回列的值作为一组值？
借助MySQLMAKE_SET()函数，我们可以将MySQL表中的列值作为一组值返回。为了理解它，我们以带有以下数据的Student_Name表为例-
mysql> Select * from Student_Name; +---------+-------+---------+ | FName | Mname | Lname | +---------+-------+---------+ | Rahul | NULL | Singh | | Gaurav | Kumar | NULL | | Harshit | NULL | Khurana | | Yash | Pal | Sharma | +---------+-------+---------+ 4 rows in set (0.00 sec)
现在，假设我们要设置“Fname”和“Lname”列的值，则下面的查询可以做到这一点-
mysql> Select MAKE_SET(1|4,fname,mname,lname)AS '(Fname,Lname)' from Student_name; +-----------------+ | (Fname,Lname) | +-----------------+ | Rahul,Singh | | Gaurav | | Harshit,Khurana | | Yash,Sharma | +-----------------+ 4 rows in set (0.00 sec)