SQL 语句中的全局变量 [英] Global Variables in SQL statement

问题描述

我在 VBA 中有以下代码:

I have the following code in VBA:

Dim strSQL As String
strSQL = "UPDATE Workstations SET MID = newvalue WHERE MID = tempvalue"
DoCmd.RunSQL strSQL

newvalue 和 tempvalue 都是全局变量，并且已经设置了值.语法明智，这有意义吗?还是我遗漏了引号?

newvalue and tempvalue are both global variables and have already been set values. Syntax wise, does this make sense? or am I missing quotation marks?

推荐答案

试试这个:

如果MID是数字:

Dim strSQL As String
strSQL = "UPDATE Workstations SET [MID] = " & newvalue & " WHERE [MID] = " & tempvalue
DoCmd.RunSQL strSQL

如果 MID 是 string(如果 newvalue/tempvalue 不包含单引号 '):

If MID is string (if newvalue/tempvalue doesn't contain single quote '):

Dim strSQL As String
strSQL = "UPDATE Workstations SET [MID] = '" & newvalue & "' WHERE [MID] = '" & tempvalue & "'"
DoCmd.RunSQL strSQL

如果 MID 是 string(如果 newvalue/tempvalue 包含单引号 '> 喜欢 newvalue="Mike's car"):

If MID is string (if newvalue/tempvalue contains single quote ' like newvalue="Mike's car"):

Dim strSQL As String
strSQL = "UPDATE Workstations SET [MID] = '" & Replace(newvalue, "'", "''") & "' WHERE [MID] = '" & Replace(tempvalue, "'", "''") & "'"
DoCmd.RunSQL strSQL

如果MID 是日期:

Dim strSQL As String
strSQL = "UPDATE Workstations SET [MID] = #" & newvalue & "# WHERE [MID] = #" & tempvalue & "#"
DoCmd.RunSQL strSQL

感谢@HansUp 在评论中指出

Thanks to @HansUp for pointing out in comments, that

MID 是函数的名称，因此在 SQL 语句中将该字段名称括起来或别名会更安全:SET [MID]

MID is the name of a function, so it would be safer to bracket or alias that field name in the SQL statement: SET [MID]

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