Question

我有以下VB语句用于将文本数据插入SQL 2008 DB。如何在执行插入时检查sFieldNameList列中是否已存在sValueList？

sInsertStatement = "INSERT " & sTableName 
                   & "(" & sFieldNameList & ") VALUES(" 
                   & Mid(sValueList , 3) & ")"

Answer 1

我会这样做：

"IF NOT EXISTS (SELECT * FROM " & sTableName * " 
                WHERE " & sFieldNameList & " = " & sValueList & ") 
 BEGIN
    "INSERT " & sTableName 
              & "(" & sFieldNameList & ") VALUES(" 
              & Mid(sValueList , 3) & ")"  
 END

（这需要适应VBScript语法！）

Answer 2

你需要做UPDATE还是INSERT？你需要的是UPSERT命令。基本上你需要一个WHERE子句，如：

where not exists (select 1 from mytable where col2='myId').

阅读here postgres是如何做到的。

sql2008没有相同的功能，只有check this blog（页面末尾）所在的位置：

USE [MyDatabase]
GO
merge into mytable as Target
using mytable2 as Source
on Target.id=Source.id
when matched then 
update set Target.name=Source.name,
Target.Salary = Source.Salary
when not matched then
insert (id,name,salary) values (Source.id,Source.name,Source.Salary);

在insert语句中查询？

2 个答案: