如何使用WHERE子句和內連接

Question

我有以下查詢我想用where子句，但它沒有顯示不同的值，請幫助我，當我使用多列的currentdate它後不顯示不同的值

SELECT CONVERT(VARCHAR(10), ts.current_datetime, 101) AS currentdatets,ts.student_id,tc.class_name,tsi.section_name,tl.test_name FROM tblstudentmarks ts 
INNER JOIN tblclassinfo tc ON 
tc.Idx = ts.class_id 
INNER JOIN tblsectioninfo tsi ON 
tsi.Idx = ts.section_id 
INNER JOIN tblsubjects su ON 
su.Idx = ts.subject_id 
INNER JOIN tbltestlist tl ON 
tl.Idx = ts.testtype 
WHERE ts.school_id = 2 AND ts.section_id = 1 AND TS.class_id = 2 AND ts.testtype = 1 

不同

Answer 1

你的問題還不清楚，但好像你只需要添加DISTINCT的選擇...

SELECT DISTINCT 
    CONVERT(VARCHAR(10), ts.current_datetime, 101) AS currentdate 
FROM tblstudentmarks ts 
    INNER JOIN tblclassinfo tc ON 
    tc.Idx = ts.class_id 
    INNER JOIN tblsectioninfo tsi ON 
    tsi.Idx = ts.section_id 
    INNER JOIN tblsubjects su ON 
    su.Idx = ts.subject_id 
    INNER JOIN tbltestlist tl ON 
    tl.Idx = ts.testtype 
WHERE 
    ts.school_id = 2 AND ts.section_id = 1 
    AND TS.class_id = 2 AND ts.testtype = 1