how to use LIKE instead of IN with multiple values? - sql

Question

I want to replace In with Like to make the query work.
SELECT
1 AS coddit, COD_CAT AS cam_cod, DES_CAT AS cam_desc,
LIVELLO_CAT AS livello, COD_CAT_PADRE AS cat_padre,
COD_L1, COD_L2, COD_L3, COD_L4, COD_L5, COD_L6
FROM
dbo.CLASS_ART
WHERE
1=1
AND TIPO_CLASS = 16 --B2B
AND LIVELLO_CAT = '0'
AND COD_CAT IN (SELECT DISTINCT CAT_MERCE.COD_CAT
FROM ART_LIST_PREZZI
INNER JOIN ART_ANA ON ART_LIST_PREZZI.COD_ART = ART_ANA.COD_ART
INNER JOIN CAT_MERCE ON ART_ANA.COD_CAT = CAT_MERCE.COD_CAT
AND ART_LIST_PREZZI.COD_LIST = 'EXPORT_002')
The comparison I would like to do with LIKE otherwise the query doesn't work well
the subquery returns more than one value and it is correct but if I use Like instead of IN I have this error message:
Query return more than 1 values

Answer 1

Using LIKE against a subquery that returns multiple records won't work. A solution would be to turn the IN condition to an EXISTS condition, like:
and exists (
select 1
from ART_LIST_PREZZI
inner join ART_ANA
on ART_LIST_PREZZI.COD_ART = ART_ANA.COD_ART
inner join CAT_MERCE
on ART_ANA.COD_CAT = CAT_MERCE.COD_CAT
and ART_LIST_PREZZI.COD_LIST = 'EXPORT_002'
where COD_CAT like '%' + CAT_MERCE.COD_CAT + '%'
)

Answer 2

Like has to be compared to a single string, so you need to set all your ids on a single string. You can do that using the for xml clause.
(SELECT DISTINCT CAST(CAT_MERCE.COD_CAT AS VARCHAR(32))
FROM ART_LIST_PREZZI
INNER JOIN ART_ANA ON ART_LIST_PREZZI.COD_ART = ART_ANA.COD_ART
INNER JOIN CAT_MERCE ON ART_ANA.COD_CAT = CAT_MERCE.COD_CAT
AND ART_LIST_PREZZI.COD_LIST = 'EXPORT_002'
FOR XML PATH(''))
Now I would delimite your ids by commas, so you don't find false positives, and compare it using like.
AND
(SELECT DISTINCT ',' + CAST(CAT_MERCE.COD_CAT AS VARCHAR(32)) + ','
FROM ART_LIST_PREZZI
INNER JOIN ART_ANA ON ART_LIST_PREZZI.COD_ART = ART_ANA.COD_ART
INNER JOIN CAT_MERCE ON ART_ANA.COD_CAT = CAT_MERCE.COD_CAT
AND ART_LIST_PREZZI.COD_LIST = 'EXPORT_002'
FOR XML PATH('')) LIKE '%,' + COD_CAT + ',%'
This would work, and you would have changed your IN operator with a LIKE operator, but I don't see the point of it, its performance would be worse than your original query.

Answer 3

Use EXISTS:
EXISTS (SELECT 1
FROM ART_LIST_PREZZI LP JOIN
ART_ANA A
ON LP.COD_ART = A.COD_ART JOIN
CAT_MERCE M
ON A.COD_CAT = M.COD_CAT AND
LP.COD_LIST = 'EXPORT_002' AND
CLASS_ART.COD_CAT LIKE M.COD_CAT
)
I assume that the logic you actually want uses wildcards:
CLASS_ART.COD_CAT LIKE CONCAT('%', M.COD_CAT, '%')
If so, it suggests an issue with the data model. Why would two columns with the same name (COD_CAT) need to be joined using LIKE instead of =.