ID有多条记录导致用于副表 连接查询时会出现重复

SELECT <strong>DISTINCT</strong>    h.house_id AS id,    title AS title,    cover_image_url AS thumb,    house_price AS price,    unit_price AS unitPrice,    house_size AS size,    `house_city_proper` AS area,    house_room AS chambers,    house_hall AS halls,    house_toilet AS toilets,    `house_partition` AS businessZone,    address AS address,    total_floor AS storey,    floor AS floor,    `house_property` AS buildings,    house_aspect AS orientation,    h.`house_usage` AS type,    's' AS tradeMode,    modDate AS lastUpdated,    0 AS sortFROM    `t_house_sold` h        LEFT JOIN    `t_promotion` p ON (h.`house_id` = p.`house_id`)WHERE    h.`house_area_id` = 66        AND h.`house_usage` = 'xzl'        AND `house_state` = 'PUB'        AND delflag = 0        AND house_agent_state = 'NORMAL'        AND house_price != 0ORDER BY `promotion_time` DESC , `modDate` DESC , `promotion_type` DESCLIMIT 500

如果没有用DISTINCT   会出现复复数据。也可以算作是处理这种重复的一种方案。

类似于：A表

1   a

2   b

B表：

1   at

1   ac

2   bc

A LEFT JOIN B 

ID为1的就会出现两条记录

所以一般副表应有唯一记录，否则易出现重复记录。

方案一：表里不出现一对多

方案二：查询结果去重