在 access 2013 中对条件更新表使用 SQL 语句

Question

I am new to databases. I am creating an Access database to track the inventory dynamics of our company. I have two tables. One is the current inventory stock, another is consumption raised by production activity. The update is done immediately after each production.

Before doing update, I want to verify the same unit is used in both stock status and consumption sheet. I try to do something like these:

Private Sub Command4_Click()
   CurrentDb.Execute "SELECT o.Unit, s.Material_Unit" & _
                     "CASE WHEN o.Unite = s.Material_Unit" & _
                     "THEN UPDATE tbl_Current_Stock As o INNER JOIN bl_Temp_Raw_Material_Consumption AS s ON o.Raw_Material = s.[Ingredient/Packaging material] Set o.Stock_Level = o.Stock_Level - s.Consumption" & _
                    " Print'Congratulations! You have successfully updated inventory balance!'" & _
                     "ElSE PRINT ' Units of source data and targeted data are not matched!'" & _
                     "Exit Sub" & _
                     "End" & _
                    "FROM tbl_Current_Stock As o, bl_Temp_Raw_Material_Consumption AS s"
END sub

But it seems some errors exist. Please help me on these codes.

Thanks.

Answer 1

Your code is totally wrong. You can not use CASE to datermine which statement to execute, UPDATE or PRINT ( PRINT is useless here, in MS Access).

You need to use either:

IF statement in your SQL query - declare o.Unite and s.Material_Unit as variables and compare them, if they match then execute update.

IF @unite = @materialunite 
BEGIN
     [Your Update Statement]
END

The other way: Declare VB variables, assign the o.Unite and s.Material_Unit values to them, and write IF - ELSE statements in VB and execute your SQL queries.