Question

查询：

  SELECT sd.ident,sd.suniq, testc, subtestc, ts.testscore, 
         metadept, ts.takendt, 
         MAX(takendt) testdate
    FROM studemo sd, stutests ts, testdef td, udefstu ud
   WHERE ts.suniq =sd.suniq
     AND td.testuniq = ts.testuniq
     AND ts.suniq = ud.suniq
     AND td.testuniq IN ('2000089', '2000090', '2000091', '2000092')
GROUP BY sd.suniq
ORDER BY suniq

收到以下错误：

Msg 8120，Level 16，State 1，Line 2 列'studemo.ident'无效选择列表，因为它不是包含在一个聚合中函数或GROUP BY子句。

我的目标是获得最新的考试成绩。我成功了，直到我尝试添加更多表格以包含更多学生信息。

Answer 1

您需要将那些不在聚合函数中的列添加到GROUP BY中，以使SQL语句有效。

GROUP BY sd.ident,sd.suniq, testc, subtestc, ts.testscore, metadept, ts.takendt

Answer 2

select sd.ident,sd.suniq, testc, subtestc, ts.testscore, metadept, ts.takendt, max(takendt)testdate
from studemo sd, stutests ts, testdef td, udefstu ud
where ts.suniq =sd.suniq
and td.testuniq = ts.testuniq
and ts.suniq = ud.suniq
and td.testuniq IN ('2000089', '2000090', '2000091', '2000092')
group by sd.ident,sd.suniq, testc, subtestc, ts.testscore, metadept, ts.takendt
order by suniq

评论：上面的代码是@Neil的意思

Answer 3

我怀疑你想要显示每个学生的最大门数，即使他们已经进行了多次测试，例如如果他们已经进行了两次测试，那么你想要显示两个测试日期，并且每行显示最大日期。如果是这种情况，那么按所有其他列进行分组将无济于事。也许尝试这个，假设SQL Server 2005或更高版本：

        WITH md AS
        (
            SELECT ts.suniq, maxdate = MAX(ts.takendt)
                FROM dbo.stutests AS ts
            INNER JOIN
                dbo.testdef AS td
                ON td.testuniq = ts.testuniq
            WHERE
                td.testuniq IN ('2000089', '2000090', '2000091', '2000092')
            GROUP BY ts.suniq
        )
        SELECT
            sd.ident,
            sd.suniq,
            testc, -- which table does this come from? why no prefix?
            subtestc, -- which table does this come from? why no prefix?
            ts.testscore,
            metadept, -- which table does this come from? why no prefix?
            ts.takendt,
            md.maxdate
        FROM
            dbo.studemo AS sd
        INNER JOIN
            dbo.stutests AS ts
            ON sd.suniq = ts.suniq
        INNER JOIN
            dbo.testdef AS td
            ON td.testuniq = ts.testuniq
        INNER JOIN
            dbo.udefstu AS ud
            ON ts.suniq = ud.suniq
        INNER JOIN md
            ON md.suniq = sd.suniq
        WHERE
            td.testuniq IN ('2000089', '2000090', '2000091', '2000092')
        ORDER BY
            sd.suniq; -- you forgot a prefix here too
            -- could cause problems if you change the query later

Answer 4

您需要将不使用聚合函数的剩余字段添加到Group By。

    select sd.ident,sd.suniq, testc, subtestc, ts.testscore, metadept, ts.takendt, max(takendt)testdate
from studemo sd, stutests ts, testdef td, udefstu ud
where ts.suniq =sd.suniq
and td.testuniq = ts.testuniq
and ts.suniq = ud.suniq
and td.testuniq IN ('2000089', '2000090', '2000091', '2000092')
group by sd.suniq, sd.ident, testc, subtestc, ts.testscore, metadept, ts.takendt
order by suniq

使用group by子句

4 个答案: