Mysql查询IN子句返回结果

Question

Good Day! All Fridays,

I have some problem in my sql query. I'm using IN class with subquery like this

SELECT
  cm.category_id,
  cd.name
FROM
  category_master cm,
  category_detail cd,
  brand_to_categories b2c
WHERE
  cm.category_id = b2c.category_id
  AND
  cd.category_id = cm.category_id
  AND
  cd.language_id = 1
  AND
  cm.status <> 2
  AND
  cm.category_id IN (SELECT DISTINCT sub_dd.categories FROM distribution_master bdm, distribution_detail bdd, subscription_category_to_brand_user sub_dd WHERE bdd.distribution_id = bdm.distribution_id AND bdm.distributor_id = 35 AND bdd.brand_id = 7191 AND sub_dd.sub_d_id = bdd.id)
  AND
  b2c.brand_id = 7191;

The following is the sub-query which is creating problem for me.

cm.category_id IN (
SELECT DISTINCT 
sub_dd.categories 
FROM 
distribution_master bdm, 
distribution_detail bdd, 
subscription_category_to_brand_user sub_dd 
WHERE 
bdd.distribution_id = bdm.distribution_id 
AND 
bdm.distributor_id = 35 
AND 
bdd.brand_id = 7191 
AND 
sub_dd.sub_d_id = bdd.id)

the result of the sub-query is like this.

3913,4517,6059,7137,7138,7139,7140,7141,7144

this result is coming from only single row in the target table because I stored these ids as string in the filed.

Now the problem is this, I can not get results of the all categories. Main query final result only return one category information which category_id is 3913. But if I run this query manually with sub-query values instead of the sub-query then it returns all the categories results.

Manual query with sub-query values is like this

SELECT
  cm.category_id,
  cd.name
FROM
  category_master cm,
  category_detail cd,
  brand_to_categories b2c
WHERE
  cm.category_id = b2c.category_id
  AND
  cd.category_id = cm.category_id
  AND
  cd.language_id = 1
  AND
  cm.status <> 2
  AND
  cm.category_id IN (3913,4517,6059,7137,7138,7139,7140,7141,7144)
  AND
  b2c.brand_id = 7191;

Please help me regarding this problem.

Sorry I forget, I'm using Mysql

Answer 1

Assuming you are using MySQL, use FIND_IN_SET:

WHERE
    ...
    FIND_IN_SET(cm.category_id,
                (SELECT DISTINCT sub_dd.categories
                 FROM distribution_master bdm,
                      distribution_detail bdd,
                      subscription_category_to_brand_user sub_dd
                 WHERE bdd.distribution_id = bdm.distribution_id AND
                       bdm.distributor_id = 35 AND
                       bdd.brand_id = 7191 AND
                       sub_dd.sub_d_id = bdd.id)) > 0

If you are using SQL Server, then we have to do a bit more work:

WHERE ',' + (SELECT DISTINCT ...) + ',' LIKE '%,' + cm.category_id + ',%'

General comment: Avoid storing CSV data in your SQL tables. MySQL almost made the problem worse by offering FIND_IN_SET and making it easier to skirt good table design.