How to convert one row into multiple rows in mysql-Mysql Tutorial-php.cn

How to convert one row into multiple rows in mysql

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Release： 2020-09-28 11:04:48

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Mysql method to turn one line into multiple lines: 1. To turn one line into multiple lines, the code is [substring_index(substring_index( a.rn,',',b.help_topic_id 1 ),',', - 1)]; 2. Convert multiple columns into multiple rows.

How to convert one row into multiple rows in mysql

Mysql method to turn one row into multiple rows:

Put

How to convert one row into multiple rows in mysql

Convert to

How to convert one row into multiple rows in mysql

SELECT
    substring_index(substring_index( a.rn,&#39;,&#39;,b.help_topic_id + 1    ),&#39;,&#39; ,- 1) AS rn
FROM
    (select &#39;1,2,3,4&#39; as rn) a  
JOIN mysql.help_topic b ON b.help_topic_id <
(length(a.rn) - length( replace(a.rn, &#39;,&#39;, &#39;&#39;)  ) + 1)

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Convert Picture A to Picture B

How to convert one row into multiple rows in mysql

Picture a

How to convert one row into multiple rows in mysql

图b

SELECT
    substring_index(substring_index( a.rn,&#39;,&#39;,b.help_topic_id + 1    ),  &#39;,&#39; ,- 1    ) AS rn
FROM
    (select SUBSTR(GROUP_CONCAT( REPEAT(CONCAT(number,&#39;,&#39;),fre) SEPARATOR &#39;&#39;),1,LENGTH(GROUP_CONCAT( REPEAT(CONCAT(number,&#39;,&#39;),fre) SEPARATOR &#39;&#39;))-1) as rn  from numbers ) a  
JOIN mysql.help_topic b ON b.help_topic_id <
(length(a.rn) - length( replace(a.rn, &#39;,&#39;, &#39;&#39;)  ) + 1)

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