Question

我在vb.net中实现此查询时遇到问题。我得到的错误消息是第一行中的“as”。这是一个本地的sql compact数据库3.5

        cmd.CommandText = "UPDATE player as a " &
                            "SET starter = 'TRUE' " &
                            "WHERE NOT EXISTS (SELECT '1' " &
                            "FROM player AS b " &
                            "WHERE(b.school = a.school) " &
                            "AND b.weight = a.weight " &
                            "AND b.skill > a.skill)"
        cmd.ExecuteNonQuery()

错误讯息 - http://i40.tinypic.com/34gms5z.png

        cmd.CommandText = "UPDATE a " &
                "SET starter = 'TRUE' " &
                "FROM player a " &
                "LEFT JOIN player b " &
                "ON a.school = b.school " &
                "AND a.weight = b.weight " &
                "AND b.skill > a.skill " &
                "WHERE b.school is NULL"
        cmd.ExecuteNonQuery()

错误讯息 - http://i40.tinypic.com/106kn86.png

Answer 1

这有用吗？

UPDATE player
SET starter = 'TRUE' 
WHERE NOT EXISTS 
(
    SELECT * FROM player b 
    WHERE b.school = player.school
    AND b.weight = player.weight 
    AND b.skill > player.skill
)

已编辑添加：

如果您创建索引，这可能会运行得更快：

CREATE INDEX player_school_weight ON player (school, weight, skill)

Answer 2

我相信你想要这个：

UPDATE pl 
SET 
    starter = 'True'
FROM 
    [Player] pl
LEFT JOIN 
    [Player] pl2 ON (pl.[School] = pl2.[School])
    AND 
    (pl.[Weight] = pl2.[Weight])
    AND 
    (pl2.[Skill] > pl.[Skill])
WHERE pl2.[School] IS NULL

SQL查询中的语法错误

2 个答案: