zoukankan      html  css  js  c++  java
  • 多表链接方法(inner join on用法)

    连接两个数据表的用法:
        FROM Member INNER JOIN MemberSort ON Member.MemberSort=MemberSort.MemberSort
        语法格式可以概括为:
        FROM 表1 INNER JOIN 表2 ON 表1.字段号=表2.字段号
       
        连接三个数据表的用法:
        FROM (Member INNER JOIN MemberSort ON Member.MemberSort=MemberSort.MemberSort) INNER JOIN MemberLevel ON Member.MemberLevel=MemberLevel.MemberLevel
        语法格式可以概括为:
        FROM (表1 INNER JOIN 表2 ON 表1.字段号=表2.字段号) INNER JOIN 表3 ON 表1.字段号=表3.字段号
       
        连接四个数据表的用法:
        FROM ((Member INNER JOIN MemberSort ON Member.MemberSort=MemberSort.MemberSort) INNER JOIN MemberLevel ON Member.MemberLevel=MemberLevel.MemberLevel) INNER JOIN MemberIdentity ON Member.MemberIdentity=MemberIdentity.MemberIdentity
        语法格式可以概括为:
        FROM ((表1 INNER JOIN 表2 ON 表1.字段号=表2.字段号) INNER JOIN 表3 ON 表1.字段号=表3.字段号) INNER JOIN 表4 ON Member.字段号=表4.字段号
       
        连接五个数据表的用法:
        FROM (((Member INNER JOIN MemberSort ON Member.MemberSort=MemberSort.MemberSort) INNER JOIN MemberLevel ON Member.MemberLevel=MemberLevel.MemberLevel) INNER JOIN MemberIdentity ON Member.MemberIdentity=MemberIdentity.MemberIdentity) INNER JOIN Wedlock ON Member.Wedlock=Wedlock.Wedlock
        语法格式可以概括为:
        FROM (((表1 INNER JOIN 表2 ON 表1.字段号=表2.字段号) INNER JOIN 表3 ON 表1.字段号=表3.字段号) INNER JOIN 表4 ON Member.字段号=表4.字段号) INNER JOIN 表5 ON Member.字段号=表5.字段号
     
  • 相关阅读:
    A1141. PAT Ranking of Institutions
    A1140. Look-and-say Sequence
    A1139. First Contact
    A1138. Postorder Traversal
    A1137. Final Grading
    A1136. Delayed Palindrome
    A1135. Is It A Red-Black Tree
    A1134. Vertex Cover
    A1133. Splitting A Linked List
    layer.open打开iframe页面的调用父页面方法及关闭
  • 原文地址:https://www.cnblogs.com/tianliang/p/3074342.html
Copyright © 2011-2022 走看看