SQL ORA-00979错误抛出

我想创建一个查询，返回一个事物的名称和国家在另一个表中的最大次数。SQL ORA-00979错误抛出

这里的结构：

ShipModels(mname, type, country, numGuns, gunSize) 
Ships(sname, hasModel, launchYear) 
Battles(bname, year) 
Outcomes(ship, battle, result)

我已经尝试了很多不同的东西，但不能让它开始工作。这是我当前的查询：

SELECT ship, country 
FROM ShipModels, Ships, Outcomes 
WHERE hasModel = mname AND ship = sname 
GROUP BY ship 
HAVING COUNT(ship) >= 
(SELECT COUNT (ship) FROM Outcomes GROUP BY ship);

Oracle错误：

ERROR at line 1: 
ORA-00979: not a GROUP BY expression

从我已阅读，当出现在SELECT语句的聚合函数将引发此错误，但是... ... ，没有。有什么我失踪？我怎样才能使这个工作？

来源

2012-12-03 Devon Roberts

如果你打算使用具有COUNT（船），我相信你需要包括COUNT（船）在你的SELECT – WebChemist

你包括在SELECT的country：

SELECT ship, country

但不是在GROUP BY。更改该行：

GROUP BY ship, country

当你改正，你会碰到另一个错误，因为子查询是不标，例如不返回一个值：

(SELECT COUNT (ship) FROM Outcomes GROUP BY ship)

你大概意思写：

(SELECT MAX(cnt) 
    FROM 
    (SELECT COUNT(ship) AS cnt FROM Outcomes GROUP BY ship) t 
)

所以，完整的查询将或多或少：

SELECT ship, country 
FROM ShipModels, Ships, Outcomes 
WHERE hasModel = mname AND ship = sname 
GROUP BY ship, country 
HAVING COUNT(ship) = 
    (SELECT MAX(cnt) 
     FROM 
     (SELECT COUNT(ship) AS cnt FROM Outcomes GROUP BY ship) t 
    ) ;

你也可以把它写更像你的企图，使用关键字ALL：

SELECT ship, country 
FROM ShipModels, Ships, Outcomes 
WHERE hasModel = mname AND ship = sname 
GROUP BY ship, country 
HAVING COUNT(ship) >= ALL 
    (SELECT COUNT(ship) AS cnt FROM Outcomes GROUP BY ship) ;

如果您使用显式连接的“现代”（SQL-92）语法，这也会很好。相反的：

FROM ShipModels, Ships, Outcomes 
WHERE hasModel = mname AND ship = sname

这是因为各种原因更好地写出：

FROM ShipModels m 
    JOIN Ships s ON s.hasModel = m.mname 
    JOIN Outcomes o ON o.ship = s.sname

来源

2012-12-03 01:34:21

正是我在找什么！非常感谢你！ –

问题在于HAVING子句中的计数（发货）。我认为这是select语句中的聚合函数。

来源

2012-12-03 00:17:43 kdmurray

SQL ORA-00979错误抛出

回答

相关问题