MySQL子查询返回不止一行

I am executing this query:

我正在执行这个查询:

SELECT
    voterfile_county.Name,
    voterfile_precienct.PREC_ID,
    voterfile_precienct.Name,
    COUNT((SELECT voterfile_voter.ID
FROM voterfile_voter
JOIN voterfile_household
WHERE voterfile_voter.House_ID = voterfile_household.ID
AND voterfile_household.Precnum = voterfile_precienct.PREC_ID)) AS Voters
FROM voterfile_precienct JOIN voterfile_county
WHERE voterfile_precienct.County_ID = voterfile_County.ID;
SELE