MySQL 直接用SQL分割字符串到数组

Posted 2020-09-14 大唐过客

承接上文：MySQL  中在不编写存储过程或函数的前提下，利用SQL 语句拆分一个字符串到数组 

主要思路其实一致：够造序列，然后结合mysql的SUBSTRING_INDEX 函数的特性分割字符串。

SET @str ="a,b,c,d,e,f,g,h,i,j,k" ;

SET @delim="," ;

SET @str_length=length(@str)- length( REPLACE (@str,@delim,\'\') )+1 ;

SELECT 
SUBSTRING_INDEX(SUBSTRING_INDEX( @str, @delim, tmp.seq),@delim, - 1) as str_split
FROM
( 
 SELECT   
s1.i + s2.i + s3.i + s4.i + s5.i + s6.i + s7.i + s8.i + s9.i+1 AS seq
FROM    (  SELECT  0 AS i  UNION ALL SELECT   1  AS i  ) s1
                    CROSS JOIN ( SELECT   0 AS i UNION ALL  SELECT  2 AS i  ) s2
                    CROSS JOIN ( SELECT   0 AS i  UNION ALL SELECT   4 AS i  ) s3
                    CROSS JOIN ( SELECT   0 AS i  UNION ALL SELECT   8 AS i  ) s4
                    CROSS JOIN ( SELECT   0 AS i   UNION ALL SELECT   16 AS i  ) s5
                    CROSS JOIN ( SELECT   0 AS i   UNION ALL SELECT   32 AS i  ) s6
                    CROSS JOIN ( SELECT   0 AS i  UNION ALL SELECT   64 AS i  ) s7
                    CROSS JOIN ( SELECT   0 AS i   UNION ALL SELECT   128 AS i  ) s8
                    CROSS JOIN ( SELECT   0 AS i  UNION ALL  SELECT   256 AS i   ) s9
ORDER BY seq
LIMIT 400
) tmp 
WHERE
tmp.seq <= @str_length