概念
A表左连接B表,即B表去对应A表
mysql语句写法示例
SELECT earlywarning.*,cars.fcNameFROM earlywarning(A表)
LEFT JOIN cars (B表)
ON cars.fcId = earlywarning.fcOtherId (连接条件)
WHERE 1=1 AND fttime >= '2018-03-10 00:00:00' AND fttime <= '2018-03-12 23:59:59'
AND fccategory = '车辆' AND earlywarning.fcSquadronId = '01010101'
查询结果示例
A left join B
A | 表 | B | 表 |
goodsName | userId | userId | username |
苹果 | 0001 | 0001 | 刘爱辉 |
柿子 | 0001 | 0001 | 刘爱辉 |
橘子 | 0002 | null | null |