MySQL实现字段分割一行转多行的示例代码_Mysql

SELECT LEFT(provinces,6),COUNT(1) FROM `region_map_copy` GROUP BY LEFT(provinces,6)

SELECT
COUNT(*),
SUBSTRING_INDEX( SUBSTRING_INDEX( a.provinces, ',', b.help_topic_id + 1 ), ',',- 1 ) AS ids
FROM
`region_map_copy` AS a
JOIN mysql.help_topic AS b ON b.help_topic_id <( LENGTH( a.provinces ) - LENGTH( REPLACE ( a.provinces, ',', '' ) ) + 1 )
GROUP BY (SUBSTRING_INDEX( SUBSTRING_INDEX( a.provinces, ',', b.help_topic_id + 1 ), ',',- 1 ) )


select p.* from t_project_info p

select p.*
from t_project_info p
where  FIND_IN_SET(6,p.thematic_library_ids)