小编Jam*_*mie的帖子

我不小心删除了phpMyAdmin中的书签查询.有什么办法可以恢复吗？

我无法尝试检索max courseid

数据:

coursename    courseid    
----------    --------
0001_Course   JAS9997
0002_Course   JAS9998
0003_Course   JAS9999
0004_Course   JAS10000

查询:

SELECT max(courseid) FROM tblcourse WHERE courseid LIKE '%JAS%'

LIKE将缩小到以JAS开头的标准.

查询仅返回JAS9999作为最大结果,但最大courseid为JAS10000.我错过了什么吗？

MySQL BETWEEN运算符和使用"> = <="之间有什么区别吗？

当我在这个查询上尝试它们时,它们会给出不同的结果.

SELECT 
      tblStaff.TitleGredCd,
      count(StudCourse1.StaffNoIC),     
      StudCourse1.StaffNoIC,
      StaffNm,
      BranchNm, 
      StDt, 
      EndDt, 
      SUM(datediff(EndDt,StDt)+1)  
      TotalDay, 
      (SELECT SUM( pembelajaranhour ) 
         FROM tblpembelajaran d 
         WHERE d.StaffNoIC = tblStaff.StaffNoIC
           AND YEAR( PembelajaranDate ) = 2011 )Totalhour,
      (SELECT SUM( datediff( kendiridate, kendiridate ) +1 ) 
         FROM tblkendiri d 
         WHERE d.StaffNoIC = tblStaff.StaffNoIC 
           AND YEAR( kendiridate ) = 2011 ) Totalkendiriday
   FROM 
      StudCourse1, 
      tblStaff 
         LEFT OUTER JOIN tblRefBranch 
            ON tblStaff.BranchCd = tblRefBranch.BranchCd, 
      tblRefTitleGred
   WHERE 
          StudCourse1.StaffNoIC = tblStaff.StaffNoIC 
      AND tblStaff.TitleGredCd = tblRefTitleGred.TitleGredCd 
     [Date Condition]
   GROUP BY …