MySQL subquery returns more than one row

Question

I am executing this query:

SELECT
    voterfile_county.Name,
    voterfile_precienct.PREC_ID,
    voterfile_precienct.Name,
    COUNT((SELECT voterfile_vote         


        

Answer 1

You can try it without the subquery, with a simple group by:

SELECT voterfile_county.Name, 
  voterfile_precienct.PREC_ID, 
  voterfile_precienct.Name, 
  count(voterfile_voter.ID)
FROM voterfile_county
JOIN voterfile_precienct 
  ON voterfile_precienct.County_ID = voterfile_County.ID
JOIN voterfile_household 
  ON voterfile_household.Precnum = voterfile_precienct.PREC_ID
JOIN voterfile_voter 
  ON voterfile_voter.House_ID = voterfile_household.ID 
GROUP BY voterfile_county.Name, 
  voterfile_precienct.PREC_ID, 
  voterfile_precienct.Name

When you use GROUP BY, any column that you are not grouping on must have an aggregate clause (f.e. SUM or COUNT.) So in this case you have to group on county name, precienct.id and precient.name.