Question

我正在尝试计算每个工作日的表中用户ID的不同数量（例如工作日1 =星期一545用户ID，工作日2 =星期二等120用户ID）。我在Access Visual Basic中这样做，但语法应该是SQL的通用。这是我的VB代码：

 sSQL = " SELECT Weekday(" & tablename & ".[DATE]) AS WEEKDAY, Count(DISTINCT " & tablename & ".[UserID]) AS User_COUNT"
 sSQL = sSQL & " FROM " & tablename
 sSQL = sSQL & " GROUP BY Weekday(" & tablename & ".[DATE])"
 qdf.SQL = sSQL

纯SQL语法应该如下所示（根据注释和测试编辑）：

     SELECT Weekday(tbl.[Date]) AS WEEKDAY, Count(DISTINCT tbl.[UserID]) AS User_COUNT
     FROM tbl
     GROUP BY Weekday(tbl.[Date])

..而[Date]是tbl中格式为Datetime的字段，[UserID]是格式为Long（带有重复项）的字段。

当我尝试运行该命令时，它告诉我“查询语法中缺少运算符......” 这是我的VB代码的问题还是SQL语法错了？

Answer 1

MS Access数据库引擎不支持COUNT(DISTINCT ...)。

要对它进行工作，请参阅此主题：SQL : how can i count distinct record in MS ACCESS作者建议使用子查询来解决问题：

SELECT
    user_id
  , COUNT(*) AS count_distinct_clients
FROM
    ( SELECT DISTINCT
          user_id, 
          client_id
      FROM tbl_sActivity
    ) AS tmp
GROUP BY
    user_id ;

根据需要更改查询代码。

<强> [编辑]

SELECT
    wday, COUNT(UserId) AS count_distinct_users
FROM
    ( SELECT DISTINCT WEEKDAY([Date]) AS wday, UserId
      FROM tblName
    ) AS tmp
GROUP BY
    wday;

SQL在Access中按工作日选择DISTINCT GROUP

1 个答案: