如何在T-SQL中使用WHERE子句

Question

以下查询未满足WHERE子句中的"a.form“条件。这与所使用的表单无关，例如，即使form=1表4中的所有经济学学生都被显示为查询的结果。

SELECT a.Form, 
       c.AcademicYear, 
       b.SubjectName, 
       b.UserID, 
       b.Password, 
       c.* 
FROM   StudentDetails.Programmes a, 
       StudentDetails.Subjects b, 
       RegistrationDetails.Registration c 
WHERE  b.SubjectName = 'Economics' 
       AND b.UserID = 'user' 
       AND b.Password = 'user' 
       AND c.Term = 1 
       AND c.academicyear = '2011/2012' 
       AND a.form = 1 
       AND ( core1 = 'Economics' 
              OR core2 = 'Economics' 
              OR core3 = 'Economics' 
              OR core4 = 'Economics' 
              OR elec1 = 'Economics' 
              OR elec2 = 'Economics' 
              OR elec3 = 'Economics' 
              OR elec4 = 'Economics' ) 

Answer 1

您应该使用以下语法：

SELECT * FROM TableA
INNER JOIN TableB
  ON TableA.name = TableB.name

它对你来说会清晰得多，而且是更好的语法。

您是否没有逻辑表关系？

请转到这个网站，它会对你很有帮助的，http://www.codinghorror.com/blog/2007/10/a-visual-explanation-of-sql-joins.html