I'm trying to select all the latitudes and longitudes for a group of users based on their id being in an array stored in another table. Here's my attempt:

SELECT latitude, longitude 
FROM userloc WHERE id = ANY( SELECT interested FROM donedeals WHERE deals_id=67);

But it gives me the following error:

ERROR:  operator does not exist: integer = integer[]
LINE 1: SELECT latitude, longitude FROM userloc WHERE id = ANY( SELE...
HINT:  No operator matches the given name and argument type(s).
       You might need to add explicit type casts.

donedeals has an int column for deals_id and an int array column for interested, which contains id's corresponding to the id column of userloc, which stores latitude and longitude:

 deals_id |  interested   
       67 | {377,387,376}
       64 | {381,384}
       66 | {377,387}

  latitude  |  longitude  | id  
 40.6439417 |  -73.964927 | 384
 40.7554919 |  -73.925891 | 380
 40.6434067 | -73.9657654 | 385
  40.746452 |   -73.90732 | 378
  40.643459 |  -73.964586 | 381
 40.6430341 | -73.9656954 | 382

This is all in Postgres 9.3.5.

I'd like to select all latitudes and longitudes for id's corresponding to the interested array for a given deals_id. This seems like it should be doable in a single call, but I can't seem to figure out the syntax. Any recommendations would be greatly appreciated.

2 Answers 2


Unfortunately = ANY (array) only works with an array literal on the right hand side, not a sub-select.

You need to "normalize" your de-normalized model, using unnest():

SELECT latitude, longitude 
FROM userloc 
WHERE id IN (SELECT unnest(interested) 
             FROM donedeals 
             WHERE deals_id = 64);

If deals_id is unique in the donedeals table, another option is to "convert" the id on the left side to an array and then use the "is contained by" operator: <@:

SELECT latitude, longitude 
FROM userloc 
WHERE array[id] <@ (SELECT interested 
                    FROM donedeals 
                    WHERE deals_id=64 );

Not sure which one would be faster. You will need to check the execution plan.

  • The 2nd query breaks if more than 1 row is returned from the subselect. Cannot happen as long as deal_id is unique, which seems like but hasn't been specified. Jan 29, 2015 at 1:52
  • @ErwinBrandstetter: you are absolutely right, thanks. I added that Jan 29, 2015 at 7:01

Typically, this whould better be rewritten as JOIN:

SELECT u.latitude, u.longitude 
FROM   userloc   u
JOIN   donedeals d ON u.id = ANY (d.interested)
WHERE  d.deals_id = 67;

I also considered the "is contained by" operator: <@, that @a_horse already mentioned. It can use a GIN index on interested. But on a second look, that's irrelevant here. This query needs indexes on userloc.id and donedeals.deals_id.

Or with unnest() in a LATERAL join (Postgres 9.3+):

SELECT u.latitude, u.longitude 
FROM   donedeals d
     , unnest(d.interested) i(id) -- implicit JOIN LATERAL
JOIN   userloc u ON u.id = i.id
WHERE  d.deals_id = 67;

The latter should be faster since it can use indexes on both userloc.id and donedeals.deals_id.

There is one possible difference: In your original, distinct rows are returned from userloc (which might still hold duplicate values for (latitude, longitude)). If (and only if) that is relevant:

SELECT DISTINCT ON (u.id)  -- id unique
       u.latitude, u.longitude 
FROM   ...

Or GROUP BY u.id with id being the PK.
You could also:

SELECT DISTINCT u.latitude, u.longitude 
FROM   ...

That would additionally fold duplicates on (latitude, longitude). It all depends on exact table definitions and requirements.

Alternative: normalize

Another option would be to normalize your schema, which would simplify the query to plain joins. Looks like a typical many-to-many relationship. Reference implementation:

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.