Question

我有以下sql将显示测试分数值：

SELECT  s.dcid, s.lastfirst, s.student_number, s.grade_level, s.schoolid,

(SELECT stc.numscore
   FROM studenttestscore stc
   JOIN testscore ts ON stc.testscoreid = ts.id
   JOIN test t on ts.testid = t.id
   JOIN studenttest st ON stc.studenttestid = st.id
   WHERE stc.studentid = s.id
   AND t.id = 451
   AND ts.id = 857
   AND st.termid LIKE '24%'
   AND ROWNUM = 1) as FALL,

(SELECT stc.numscore
   FROM studenttestscore stc
   JOIN testscore ts ON stc.testscoreid = ts.id
   JOIN test t on ts.testid = t.id
   JOIN studenttest st ON stc.studenttestid = st.id
   WHERE stc.studentid = s.id
   AND t.id = 501
   AND ts.id = 1001
   AND st.termid LIKE '24%'
   AND ROWNUM = 1) as WINTER,

(SELECT stc.numscore
   FROM studenttestscore stc
   JOIN testscore ts ON stc.testscoreid = ts.id
   JOIN test t on ts.testid = t.id
   JOIN studenttest st ON stc.studenttestid = st.id
   WHERE stc.studentid = s.id
   AND t.id = 551
   AND ts.id = 1051
   AND st.termid LIKE '24%'
   AND ROWNUM = 1) as SPRING

FROM students s

WHERE s.grade_level = 1 

ORDER BY s.lastfirst

如上所述，这将返回所有学生以及他们在秋季，冬季和春季测试期间的分数。我现在需要做的是将学生名单限制在秋季和冬季期间他们的分数低于特定基准的学生名单。我知道我可以通过添加WHERE子句来实现这一点：

WHERE s.grade_level = 1
AND (SELECT stc.numscore
   FROM studenttestscore stc
   JOIN testscore ts ON stc.testscoreid = ts.id
   JOIN test t on ts.testid = t.id
   JOIN studenttest st ON stc.studenttestid = st.id
   WHERE stc.studentid = s.id
   AND t.id = 451
   AND ts.id = 857
   AND st.termid LIKE '24%'
   AND ROWNUM = 1) < 28

AND (SELECT stc.numscore
   FROM studenttestscore stc
   JOIN testscore ts ON stc.testscoreid = ts.id
   JOIN test t on ts.testid = t.id
   JOIN studenttest st ON stc.studenttestid = st.id
   WHERE stc.studentid = s.id
   AND t.id = 501
   AND ts.id = 1001
   AND st.termid LIKE '24%'
   AND ROWNUM = 1) < 37

我的问题是，这是创建选择标准的最有效方法吗？有没有办法可以回顾所选分数的别名，FALL和WINTER？当我用

测试它时，它不起作用

WHERE s.grade_level = 1
AND FALL < 28
AND WINTER < 37

Answer 1

您只需将Select嵌套在派生表（也称为内联视图）中，然后就可以使用WHERE中的别名列：

SELECT *
FROM 
 (
   SELECT  s.dcid, s.lastfirst, s.student_number, s.grade_level, s.schoolid,

    (SELECT stc.numscore
       FROM studenttestscore stc
       JOIN testscore ts ON stc.testscoreid = ts.id
       JOIN test t ON ts.testid = t.id
       JOIN studenttest st ON stc.studenttestid = st.id
       WHERE stc.studentid = s.id
       AND t.id = 451
       AND ts.id = 857
       AND st.termid LIKE '24%'
       AND ROWNUM = 1) AS FALL,

    (SELECT stc.numscore
       FROM studenttestscore stc
       JOIN testscore ts ON stc.testscoreid = ts.id
       JOIN test t ON ts.testid = t.id
       JOIN studenttest st ON stc.studenttestid = st.id
       WHERE stc.studentid = s.id
       AND t.id = 501
       AND ts.id = 1001
       AND st.termid LIKE '24%'
       AND ROWNUM = 1) AS WINTER,

    (SELECT stc.numscore
       FROM studenttestscore stc
       JOIN testscore ts ON stc.testscoreid = ts.id
       JOIN test t ON ts.testid = t.id
       JOIN studenttest st ON stc.studenttestid = st.id
       WHERE stc.studentid = s.id
       AND t.id = 551
       AND ts.id = 1051
       AND st.termid LIKE '24%'
       AND ROWNUM = 1) AS SPRING

    FROM students s

    WHERE s.grade_level = 1
 ) dt
WHERE FALL < 28
AND WINTER < 37

Answer 2

使用公用表表达式，您可以引用主查询的where子句中CTE select语句的字段。他们还清理了一点结构，重用限制了你需要复制+粘贴公共谓词的次数（例如 - 和st.termid LIKE＆＃39; 24％＆＃39;）

WITH TermTestData AS (
    SELECT  ts.testid
        ,   ts.id
        ,   stc.numscore
        ,   stc.studentid
    FROM    studenttestscore AS stc
    JOIN    testscore AS ts
        ON  ts.id = stc.testscoreid
    JOIN    studenttest AS st
        ON  st.id = stc.testscoreid
    WHERE   st.termid LIKE '24%'
), SemesterScores AS (
    SELECT  s.dcid, s.lastfirst, s.student_number, s.grade_level, s.schoolid
        ,   (SELECT td.numscore
             FROM   TermTestData AS td
             WHERE  td.studentid = s.id
             AND td.id = 451
             AND td.id = 857
             AND ROWNUM = 1) as FALL
        ,   (SELECT td.numscore
             FROM   TermTestData AS td
             WHERE  td.studentid = s.id
             AND td.id = 501
             AND td.id = 1001
             AND ROWNUM = 1) as WINTER
        ,   (SELECT td.numscore
             FROM   TermTestData AS td
             WHERE  td.studentid = s.id
             AND td.id = 551
             AND td.id = 1051
             AND ROWNUM = 1) as SPRING
    FROM    students AS s
)
SELECT  *
FROM    SemesterScores
WHERE   FALL < 28
AND     WINTER < 37

备注：如果您使用的是Oracle 11g，则可以转动数据以避免使用单值字段的select语句

Answer 3

如果这是MYSQL，你可以试试它：

WHERE s.grade_level = 1
HAVING FALL < 28 AND WINTER < 37

我相信“HAVING”会再次通过，并会选择别名。

返回WHERE子句中的选定值

3 个答案: