Question

我使用以下SQL（使用SQL Server 2016）来透射LMS（Moodle）的测试结果列表：

SELECT * 
FROM 
    (SELECT
         u.firstname AS name,
         u.lastname AS last_name,
         u.idnumber AS id_number,
         gi.itemname AS exam_name,
         CAST(gg.finalgrade / gi.grademax * 100 AS integer) AS grade
     FROM  
         mdl_grade_grades gg 
     INNER JOIN 
         mdl_grade_items gi ON gg.itemid = gi.id 
     INNER JOIN 
         mdl_course c ON gi.courseid = c.id 
     INNER JOIN 
         mdl_user u ON gg.userid = u.id
     WHERE 
         (gi.itemname IS NOT NULL) 
         AND (gi.courseid = 123)) SOURCE
PIVOT 
    (MAX(grade)
     FOR exam_name IN ([Exam ABC], [Exam DEF], [Exam GHI],
                       [Exam JKL], [Exam XYZ])
    ) PIVT
ORDER BY 
    id_number

结果将是：

name    last name   id number   division    region      branch      Exam ABC    Exam DEF    Exam GHI    Exam JKL    Exam XYZ
John    Tester      3343664     ABC         WEST RGN    A AGY       65                                  44
Kenny   Quipton     4342423     DDA         CENTRAL     RGN FRN     88          66          90                      89
Molefi  Manase      5456545     CCS         ABC RGN     XXX SOL     74          90          85          80          77

我唯一的问题是考试名称必须在FOR IN(...)列表中进行硬编码，因此每次更改内容时都必须手动更新列表。

可以使用动态SQL重写此SQL吗？

更好的是 - 使用Stuff()或FOR XML PATH还是其他什么？

我无法使用存储过程（应用程序不支持它们）。

Answer 1

不需要存储过程和FOR XML Path用于逗号连接。只需将以下代码放入查询构建器并将其发送到数据库服务器即可。

DECLARE @SQL VARCHAR(MAX)='', @COL_NAMES VARCHAR(MAX)='';


--PREPARING EXAM NAMES LIST
SELECT @COL_NAMES = @COL_NAMES+ itemname+',' FROM (
SELECT DISTINCT  gi.itemname 
FROM mdl_grade_grades gg 
INNER JOIN mdl_grade_items gi ON gg.itemid = gi.id 
INNER JOIN mdl_course c ON gi.courseid = c.id 
INNER JOIN mdl_course_categories cc ON c.category = cc.id 
INNER JOIN mdl_user u ON gg.userid = u.id
WHERE (gi.itemname IS NOT NULL) 
AND (gi.courseid = 123)
);

SELECT @COL_NAMES = LEFT(@COL_NAMES,LEN(@COL_NAMES)-1 );



--PREPARING DYNAMIC QUERY
SELECT @SQL = 
'SELECT * FROM (
    SELECT
        u.firstname AS name,
        u.lastname AS last_name,
        u.idnumber AS id_number,
        gi.itemname AS exam_name,
        CAST(gg.finalgrade / gi.grademax * 100 AS integer) AS grade
    FROM mdl_grade_grades gg 
    INNER JOIN mdl_grade_items gi ON gg.itemid = gi.id 
    INNER JOIN mdl_course c ON gi.courseid = c.id 
    INNER JOIN mdl_course_categories cc ON c.category = cc.id 
    INNER JOIN mdl_user u ON gg.userid = u.id
    WHERE (gi.itemname IS NOT NULL) 
    AND (gi.courseid = 123)
) SOURCE
PIVOT (
    MAX(grade)
    FOR exam_name IN ('+@COL_NAMES+'
    )
) PIVT
ORDER BY id_number'


EXEC (@SQL);

Answer 2

这使用for xml但是应该以相同的方式工作

DECLARE @exams nvarchar(max), @sql nvarchar(max)
SET     @exams = SELECT STUFF(SELECT ',',  + QUOTENAME(t.itemname)
                         FROM (
                           SELECT DISTINCT gi.itemname 
                           FROM   mdl_grade_items gi 
                           WHERE  gi.itemname IS NOT NULL AND gi.courseid = 123
                           ORDER BY gi.itemname 
                         ) t
              FOR XML PATH(''), 0, 1, '')

SET    @sql = N'
    SELECT * 
    FROM 
       (SELECT
           u.firstname AS name,
           u.lastname AS last_name,
           u.idnumber AS id_number,
           gi.itemname AS exam_name,
           CAST(gg.finalgrade / gi.grademax * 100 AS integer) AS grade
        FROM  
           mdl_grade_grades gg 
        INNER JOIN 
           mdl_grade_items gi ON gg.itemid = gi.id 
        INNER JOIN 
           mdl_course c ON gi.courseid = c.id 
        INNER JOIN 
           mdl_user u ON gg.userid = u.id
        WHERE 
           (gi.itemname IS NOT NULL) 
           AND (gi.courseid = 123)) SOURCE
    PIVOT 
       (MAX(grade)
         FOR exam_name IN (' + @exams + ')
       ) PIVT
    ORDER BY 
       id_number 
'

EXEC sp_executesql @sql

动态SQL枢轴

2 个答案: