mysql查询赋值、修改拼接字符串

sql中修改字符串类型的字段可以这么拼接：update tbName set UserName='abc'+UserName;

但mysql中就不行了，需要这样：update tbName set UserName=CONCAT('abc',UserName);

把查询出来的多个值，赋值给多个变量，

sql：SELECT @oldOrderId=M_ORDERID,@oldParentId=M_PARENTID,@oldOrderPath=M_ORDERPATH FROM S_Menu WHERE M_ID=id;

mysql：SELECT M_ORDERID,M_PARENTID,M_ORDERPATH INTO oldOrderId,oldParentId,oldOrderPath FROM S_Menu WHERE M_ID=id;

sql中声明变量要加@，mysql中不用加@。