SQL 左连接关联查询怎么去重.

Question

SELECT

h.house_code,
h.house_name,
h.create_time,
l.latitude,
l.longitude,
f.file_code

FROM

t_hkp_hos_house h
LEFT JOIN t_hkp_hos_location l ON l.location_code = h.location_code
LEFT JOIN t_hkp_sys_file_relation f ON f.owner_code = h.house_code 
AND file_use = '1',
(
SELECT
    h2.ID
FROM
    t_hkp_hos_house h2
    LEFT JOIN t_hkp_hos_location l ON l.location_code = h2.location_code
WHERE
    h2.house_purpose IN ( '3', '2' ) 
    AND h2.house_status = '1' 
    AND h2.city = '310100' 
GROUP BY
    h2.ID 
) b 

WHERE

h.id = b.ID 

ORDER BY

create_time DESC 
LIMIT 50

Answer 1

去重可以通过分组group by 或者 distinct 来实现。