test1表应用test2表的字段,test1表把test2表的id通过逗号分隔存到test1表中的一个字段
字段分隔sql:
SELECT
a.id as id,
a.name as name,
substring_index(
substring_index(
a.products,
',',
(b.help_topic_id + 1)
),
',' ,- (1)
) AS shareholder
FROM
(
school.test a
JOIN mysql.help_topic b ON (
(
b.help_topic_id < (
(
length(a.products) - length(
REPLACE (a.products, ',', '')
)
) + 1
)
)
)
)
字段分隔查询出来的sql是多条的,多表联合查询怎么关联:
创建一个视图,把上面查询语句放到视图中,使用视图名称多表查询关联,例如上面sql视图名称为 view1,和test2表关联查询
SELECT
*
FROM
view1 a,
test2 b
WHERE
a.shareholder = b.id;