我需要一个将多个列中的多个值拆分为另一列的帮助。下面是一个示例
CREATE TABLE split
(
`Col_1` VARCHAR(120),
`Col_2` VARCHAR(50),
`Col_3` VARCHAR(20),
`Col_4` VARCHAR(50)
);
Insert into split (Col_1,Col_2,Col_3,Col_4) values ('ABC','1','10',null);
Insert into split (Col_1,Col_2,Col_3,Col_4) values ('DEF','2,3','30,40',null);
Insert into split (Col_1,Col_2,Col_3,Col_4) values ('GHI','4,5','50','500,600,700');
select * from split;
+-------+-------+-------+-------------+
| Col_1 | Col_2 | Col_3 | Col_4 |
+-------+-------+-------+-------------+
| ABC | 1 | 10 | NULL |
| DEF | 2,3 | 30,40 | NULL |
| GHI | 4,5 | 50 | 500,600,700 |
+-------+-------+-------+-------------+
我不是这方面的专家，但是一直在玩耍，并且设法仅将col_2分成多个行，如下所示：
SELECT
Col_1,Col_2,Col_3,Col_4,
SUBSTRING_INDEX(SUBSTRING_INDEX(split.Col_2, ',', numbers.n), ',', -1) Col_2_NEW,
SUBSTRING_INDEX(SUBSTRING_INDEX(split.Col_3, ',', numbers.n), ',', -1) Col_3_NEW,
SUBSTRING_INDEX(SUBSTRING_INDEX(split.Col_4, ',', numbers.n), ',', -1) Col_4_NEW
FROM
(SELECT 1 n UNION ALL SELECT 2
UNION ALL SELECT 3 UNION ALL SELECT 4) numbers INNER JOIN split
ON CHAR_LENGTH(split.Col_2) - CHAR_LENGTH(REPLACE(split.Col_2, ',', ''))>=numbers.n-1
ORDER BY Col_2, n;
+-------+-------+-------+-------------+-----------+-----------+-----------+
| Col_1 | Col_2 | Col_3 | Col_4 | Col_2_NEW | Col_3_NEW | Col_4_NEW |
+-------+-------+-------+-------------+-----------+-----------+-----------+
| ABC | 1 | 10 | NULL | 1 | 10 | NULL |
| DEF | 2,3 | 30,40 | NULL | 2 | 30 | NULL |
| DEF | 2,3 | 30,40 | NULL | 3 | 40 | NULL |
| GHI | 4,5 | 50 | 500,600,700 | 4 | 50 | 500 |
| GHI | 4,5 | 50 | 500,600,700 | 5 | 50 | 600 |
+-------+-------+-------+-------------+-----------+-----------+-----------+
但是，我也想将col_3和col_4拆分为new，因此它的输出如下。
+-------+-------+-------+-------------+-----------+-----------+-----------+
| Col_1 | Col_2 | Col_3 | Col_4 | Col_2_NEW | Col_3_NEW | Col_4_NEW |
+-------+-------+-------+-------------+-----------+-----------+-----------+
| ABC | 1 | 10 | NULL | 1 | 10 | NULL |
| DEF | 2,3 | 30,40 | NULL | 2 | 30 | NULL |
| DEF | 2,3 | 30,40 | NULL | 2 | 40 | NULL |
| DEF | 2,3 | 30,40 | NULL | 3 | 30 | NULL |
| DEF | 2,3 | 30,40 | NULL | 3 | 40 | NULL |
| GHI | 4,5 | 50 | 500,600,700 | 4 | 50 | 500 |
| GHI | 4,5 | 50 | 500,600,700 | 4 | 50 | 600 |
| GHI | 4,5 | 50 | 500,600,700 | 4 | 50 | 700 |
| GHI | 4,5 | 50 | 500,600,700 | 5 | 50 | 500 |
| GHI | 4,5 | 50 | 500,600,700 | 5 | 50 | 600 |
| GHI | 4,5 | 50 | 500,600,700 | 5 | 50 | 700 |
+-------+-------+-------+-------------+-----------+-----------+-----------+
到目前为止，我已经进行了搜索，他们只将行分成一列，却找不到类似于我的问题。 也许缺少一些联接或某些联合，我不知道，因为我不擅长查询。 有人能帮我一下吗？而不要求我阅读指南或手册：-）
预先感谢
答案 0 :(得分：1)
您可以尝试推荐in this thread here之一。
类似于
SELECT s.[Col_1], Split.a.value('.', 'VARCHAR(100)') AS String
FROM (SELECT [Col_1],
CAST ('<M>' + REPLACE([Col_2], ',', '</M><M>') + '</M>' AS XML) AS String
FROM split) AS s
CROSS APPLY String.nodes ('/M') AS Split(a);
在您的列上进行迭代应该可以正常工作。
编辑：对不起，这不是MySQL。可行的解决方案请参见下文。
以下代码应适用于前两列。
1。）创建表：
CREATE TABLE split(
`Col_1` VARCHAR(120),
`Col_2` VARCHAR(50),
`Col_3` VARCHAR(20),
`Col_4` VARCHAR(50)
);
INSERT INTO split (Col_1,Col_2,Col_3,Col_4) values ('ABC','1','10',null);
INSERT INTO split (Col_1,Col_2,Col_3,Col_4) values ('DEF','2,3','30,40',null);
INSERT INTO split (Col_1,Col_2,Col_3,Col_4) values ('GHI','4,5','50','500,600,700');
这导致
SELECT * FROM split;
Col_1 Col_2 Col_3 Col_4
ABC 1 10 (null)
DEF 2,3 30,40 (null)
GHI 4,5 50 500,600,700
2。）在Col_2中拆分字符串：
SELECT
split.Col_1,
SUBSTRING_INDEX(SUBSTRING_INDEX(split.Col_2, ',', numbers.n), ',', -1) Col_2,
Col_3,
Col_4
FROM
(select 1 n UNION ALL
select 2 UNION ALL select 3 UNION ALL
select 4 UNION ALL select 5) numbers INNER JOIN split
ON CHAR_LENGTH(split.Col_2)
-CHAR_LENGTH(REPLACE(split.Col_2, ',', ''))>=numbers.n-1
ORDER BY Col_1, Col_2;
3。）结果：
Col_1 Col_2 Col_3 Col_4
ABC 1 10 (null)
DEF 2 30,40 (null)
DEF 3 30,40 (null)
GHI 4 50 500,600,700
GHI 5 50 500,600,700
这是一个带有以上代码的SQL提琴：http://sqlfiddle.com/#!9/948fcb/4。 您应该可以从那里进行迭代。如果您需要更多指导，只需评论此帖子。
重要警告：在一列中最多可以使用5个逗号分隔的字符串。
解决方案的灵感来自fthiella对SQL split values to multiple rows的回答。
答案 1 :(得分：0)
只想回答最终查询，这将根据需要提供所需的输出。 将其张贴在这里，也许会帮助其他人。
SELECT distinct Col_1,Col_2,Col_3,Col_4,
SUBSTRING_INDEX(SUBSTRING_INDEX(t.Col_2, ',', n.n), ',', -1) Col_2_New,
SUBSTRING_INDEX(SUBSTRING_INDEX(t.Col_3, ',', n1.n), ',', -1) Col_3_New,
SUBSTRING_INDEX(SUBSTRING_INDEX(t.Col_4, ',', n2.n), ',', -1) Col_4_New
FROM split t CROSS JOIN
(
SELECT a.N + b.N * 10 + 1 n
FROM
(SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 ) a
,(SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 ) b
,(SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 ) c
ORDER BY n
) n,
(
SELECT a.N + b.N * 10 + 1 n
FROM
(SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 ) a
,(SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 ) b
,(SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 ) c
ORDER BY n
) n1,
(
SELECT a.N + b.N * 10 + 1 n
FROM
(SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 ) a
,(SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 ) b
,(SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 ) c
ORDER BY n
) n2
WHERE coalesce(n.n,'0') <= 1 + (LENGTH(coalesce(t.Col_2,'0')) - LENGTH(REPLACE(coalesce(t.Col_2,'0'), ',', '')))
AND coalesce(n1.n,'0') <= 1 + (LENGTH(coalesce(t.Col_3,'0')) - LENGTH(REPLACE(coalesce(t.Col_3,'0'), ',', '')))
AND coalesce(n2.n,'0') <= 1 + (LENGTH(coalesce(t.Col_4,'0')) - LENGTH(REPLACE(coalesce(t.Col_4,'0'), ',', '')))
ORDER BY 1,2,3,4,5,6,7 ;