Question

如果inventory.nick是NULL? INSERT INTO gold_log (nick, amount, stream_online, modification_type, dt) SELECT inventory.nick, SUM(inventory.stat_2*.01), False, 12, NOW() FROM inventory INNER JOIN equipment_shoes ON inventory.id=equipment_shoes.id AND inventory.item=8 INNER JOIN gold_log ON inventory.nick=gold_log.nick AND gold_log.dt > FROM_UNIXTIME(1423421534.32);，我怎么能不为以下声明做任何INSERT？提前谢谢你！

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Answer 1

在where子句中添加该条件？

INSERT INTO gold_log (nick, amount, stream_online, modification_type, dt) 
    SELECT inventory.nick, SUM(inventory.stat_2*.01), False, 12, NOW()
    FROM inventory
        INNER JOIN equipment_shoes ON
        inventory.id=equipment_shoes.id
        AND inventory.item=8
        INNER JOIN gold_log ON 
        inventory.nick=gold_log.nick
        AND gold_log.dt > FROM_UNIXTIME(1423421534.32);
    HAVING
        inventory.nick IS NOT NULL

（由WHERE引起的隐式分组）将HAVING更改为SUM

此外，您可以使列本身不可为空：

ALTER TABLE inventory MODIFY COLUMN nick VARCHAR(200) NOT NULL;

但仅凭这一点无法解决问题。如果列不可为空，并且列具有默认值，则如果查询中nick为空，则所有新行都将获得此默认值。如果它没有默认值，则插入将完全失败，包括那些填充了nick的行。因此对insert语句本身的更改是最重要的：它将跳过那些没有nick的行。

Answer 2

只需添加IS NOT NULL条件：

INSERT INTO gold_log (nick, amount, stream_online, modification_type, dt) 
    SELECT inventory.nick, SUM(inventory.stat_2*.01), False, 12, NOW()
    FROM inventory
        INNER JOIN equipment_shoes ON
        inventory.id=equipment_shoes.id
        AND inventory.item=8
        INNER JOIN gold_log ON 
        inventory.nick=gold_log.nick
        AND gold_log.dt > FROM_UNIXTIME(1423421534.32)
        WHERE inventory.nick IS NOT NULL;

MySQL不要INSERT如果NULL字段

2 个答案: