SQL in (@Variable) query

Question

I have the following code, the problem is that my variable list @LocationList is essentially a csv string. When I use this as part of the where LocationID in (@LocationList

Answer 1

I often have this requirement, and SOMETIME, if you know very well the column you are searching on [the size/format/length], you can do a kind of REGEX.

Something like this :

  DECLARE @MyListOfLocation varchar(255)
  set @MyListOfLocation  = '|1|32|36|24|3|'

  Select LocationID 
  from  Table 
  where @MyListOfLocation like '%|' +  LocationID + '|%'

NOTE : the PIPE character is used to protect the query from returning any LocationID that contains a single character (the '1', for example).

Here is a complete working example :

DECLARE @MyListOfLocation varchar(255)
set @MyListOfLocation  = '|1|11|21|'

SELECT LocationName
FROM (
        select '1' as LocationID, 'My Location 1' as LocationName
        union all
        select '11' as LocationID, 'My Location 11' as LocationName
        union all
        select '12' as LocationID, 'My Location 12' as LocationName
        union all
        select '13' as LocationID, 'My Location 13' as LocationName
        union all
        select '21' as LocationID, 'My Location 21' as LocationName
    ) as MySub
where @MyListOfLocation like '%|' + LocationID + '|%'

WARNING! This method is not Index friendly!

If you want do add some IN(@MyListOfLocation) in all that, to leverage use of INDEXES, you can modify your script do to :

SELECT MyDATA.* 
FROM   HugeTableWithAnIndexOnLocationID as MyDATA 
WHERE  LocationID in (
      Select LocationID 
      from  Table 
      where @MyListOfLocation like '%|' +  LocationID + '|%')