IIF语句( Ms-Access )

Question

我有三个表：

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我使用下面的代码将它们连接在一起(我使用Delphi)：

ADOQ.SQL.Text := 'select a.IdArt as [Code d''Article], '+
                   'a.Nom,'+
                   'Str(a.Prix)+" TND" as Prix, '+
                   '(select Str(sum(QteEntree))+" "+a.unit from Stock where IdArt = a.IdArt group by IdArt) as [Quantite Entree],' +
                   '(select Str(sum(Qte))+" "+a.unit from Sold where IdArt = a.IdArt group by IdArt) as [Quantite Vendu],'+
                   'Str((select sum(QteEntree) from Stock where IdArt = a.IdArt group by IdArt) -' +
                   '(select sum(Qte) from Sold where IdArt = a.IdArt group by IdArt))+" "+a.unit as [Quantite Existe]'+

                   'from Article a ';

​

​

正如您所看到的，当一个表中缺少记录时，它会向DbGrid返回Null，所以我想用"0“替换丢失的记录。我试过这段代码：

ADOQ.SQL.Text := 'select a.IdArt as [Code d''Article], '+
                   'a.Nom,'+
                   'Str(a.Prix)+" TND" as Prix, '+
                   '(select Str(sum(QteEntree))+" "+a.unit from Stock where IdArt = a.IdArt group by IdArt) as [Quantite Entree],' +
                   '(select IIF( IsNull(sum(Qte)), "111" , Format( sum(Qte),"00.00") ) from Sold where IdArt = a.IdArt group by IdArt) as [Quantite Vendu],'+
                   'Str((select sum(QteEntree) from Stock where IdArt = a.IdArt group by IdArt) -' +
                   '(select sum(Qte) from Sold where IdArt = a.IdArt group by IdArt))+" "+a.unit as [Quantite Existe]'+

                   'from Article a ';

但是没有什么变化，尽管这段代码运行得很好：

ADOQ.SQL.Text := 'Select a.IdArt,IIF(( IsNull( s.qte) ), "00,00" , Format( (s.qte),"00.00") ) from Article a left join sold s on s.IdArt = a.IdArt';

​

​

我在这里做错了什么？

Answer 1

ok找到了解决方案：

iif( isnull((select sum(QteEntree) from Stock where IdArt = a.IdArt group by IdArt)) ,0, (select sum(QteEntree) from Stock where IdArt = a.IdArt group by IdArt) )  

Answer 2

尝试去掉“group by IdArt”部分-它们似乎没有必要，因为您已经在WHERE子句中排除了所有其他部分。

否则，像这样的东西可能会改善您编写查询的方式：

select 
    a.IdArt as [Code d''Article], 
    a.Nom,
    Str(a.Prix)+" TND" as Prix, 
    Str(sum(stock.QteEntree))+" "+a.unit as [Quantite Entree],
    IIF( IsNull(sum(sold.Qte)), "111" , Format( sum(sold.Qte),"00.00") ) as [Quantite Vendu],
    Str(sum(stock.QteEntree) - sum(sold.Qte))+" "+a.unit as [Quantite Existe]

from Article a 
left join stock on a.IdArt = stock.IdArt
left join sold on a.IdArt = sold.IdArt
group by a.IdArt, a.Nom, a.Prix, a.unit

不过，您可能需要对此进行调整

实际上，我更喜欢从上面写下这句话：

IIF( IsNull(sum(sold.Qte)), "111" , Format( sum(sold.Qte),"00.00") ) as [Quantite Vendu],

就像这样：

Format( sum( IIF( IsNull( sold.Qte ) , 0, sold.Qte ) ), "00.00" ) as [Quantite Vendu],

同样，我不是100%确定这是否有效，我只是在看你的函数的顺序和逻辑