set @s = 1; set @f = ''; DECLARE v1 INT DEFAULT 5; SET v1 = v1 - 1 while @s<10 @f = CONCAT(@f,v1); set v1= v1+1; end WHILE; select @f; 有问题吗?报以下错误。MySql刚入门。Query OK, 0 rows affected (0 ms)Query OK, 0 rows affected (15 ms)You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DECLARE v1 INT DEFAULT 5' at line 1
s1 = 'a,b,d'
则返回3;s1中有a,b,d,若s1 = 'a,b,z' 则返回2;
右s1 = 'aa,bb' 则返回0;
set @f = '';
DECLARE v1 INT DEFAULT 5;
SET v1 = v1 - 1
while @s<10
@f = CONCAT(@f,v1);
set v1= v1+1;
end WHILE;
select @f;
有问题吗?报以下错误。MySql刚入门。Query OK, 0 rows affected (0 ms)Query OK, 0 rows affected (15 ms)You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DECLARE v1 INT DEFAULT 5' at line 1
拆分S1字符串,用REPALCE替换S1的字符为'',用LEN原始-LEN替换后的字符串,得到长度,
其中拆分S1字符串难点
MYSQL能用C#下的函数?但这里是存储过程要用啊。
s1关键字的顺序不一定按s0的顺序来啊。s0 = 关键字1,关键字2,关键字3,关键字4
s1 = 关键字2,关键字1
与
s1 = 关键字1,关键字2得出来的结果得一样。
我也是这样的想法。但MYSQL写起函数来很是麻烦。不知道效率如何?
用SUBSTRING_INDEX(s0,',',i)取第几次出现