假设我有两张桌子。表T1
像:
Game Player Points Assists
1 1 10 5
1 2 5 10
T2
喜欢:
Game Player Fouls Turnovers
1 1 5 5
1 2 10 10
我想创建一个视图,每个玩家一行和一个新的字段rating
,其中rating
是每个玩家的Points, Assists, Fouls,Turnovers
的相等加权和。 (即评分= .25 *积分+ .25 *助攻+ .25 * Fouls + .25 *失误)
我创建了视图:
CREATE VIEW `player_view` AS (
SELECT Player,
SUM(
Points *0.25 +
Assists *0.25 +
Fouls *0.25 +
Turnovers *0.25) AS Rating)
FROM T1 INNER JOIN T2 ON
T1.Player = T2.Player
AND T1.Game = T2.Game
GROUP BY Player
但不是返回一个值,我得到所有NULL
的Rating
:
Player Rating
1 NULL
2 NULL
最初,我面对的是
Expression #2 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'support_desk.mod_users_groups.group_id' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by
所以我通过only_full_group_by
禁用了SET sql_mode='STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION'
所以现在,虽然视图返回结果集,但Ratings
都是NULL。请协助。
似乎你错过了总和之间的操作符,例如+可能是你在关键字段中有一些隐藏的字符所以..尝试trim()
CREATE VIEW `player_view` AS
SELECT Player,
SUM(
t1.Points*0.25 +
t1.Assists*0.25 +
t2.Fouls*0.25 +
t2.Turnovers*0.25) AS Rating
)
FROM T1
INNER JOIN T2 ON
trim(T1.Player) = trim(T2.Player)
AND trim(T1.Game) = trim(T2.Game);
GROUP BY Player
select * from player_view;