列名sql isull子句，其中

问题描述

| 我无法在IdCell列上创建where子句，但可以执行\“ order by \”。 sql Server对列名称说错误

    select 
    *,(ISNULL(Table_Adresses.IdCellule,Table_Clients.IdCellule)) as IdCell
    from Table_Tickets 
    left join Table_Postes on Table_Postes.IdPoste = Table_Tickets.IdPoste
    left join Table_Adresses on Table_Adresses.IdAdresse = Table_Postes.IdAdressePhysique
    left join Table_Clients on Table_Clients.IdClient = Table_Tickets.IdClient
    where idtypeticket=2 and 
    isnull(bcloture,0)=0 and 
    IdCell =4 --problem here
    order by IdCell

为什么我不能在IdCell上找到位置？ 谢谢     

解决方法

        您不能以这种方式使用别名列，您需要执行以下操作：

and (ISNULL(Table_Adresses.IdCellule,Table_Clients.IdCellule)) = 4

    ,        尽管SQL（语言）迫使您以

SELECT-FROM-WHERE-ORDER BY

的顺序构造查询，但是（有效地）它以

FROM-WHERE-SELECT-ORDER BY

的顺序执行。这就是为什么可以在

ORDER BY

子句中使用

AS

子句（\“列别名\”）

IdCell

而不在

WHERE

子句中使用的原因，即

IdCell

不在

WHERE

子句的范围内，因为它只会在以后出现。     ,        

   select 
    *,(ISNULL(Table_Adresses.IdCellule,Table_Clients.IdCellule)) as IdCell
    from Table_Tickets 
    left join Table_Postes on Table_Postes.IdPoste = Table_Tickets.IdPoste
    left join Table_Adresses on Table_Adresses.IdAdresse = Table_Postes.IdAdressePhysique
    left join Table_Clients on Table_Clients.IdClient = Table_Tickets.IdClient
    where idtypeticket=2 and 
    isnull(bcloture,0)=0 and 
    (ISNULL(Table_Adresses.IdCellule,Table_Clients.IdCellule)) =4 
    order by IdCell

    ,        

select 
    *,Table_Clients.IdCellule)) as IdCell
    from Table_Tickets 
    left join Table_Postes on Table_Postes.IdPoste = Table_Tickets.IdPoste
    left join Table_Adresses on Table_Adresses.IdAdresse = Table_Postes.IdAdressePhysique
    left join Table_Clients on Table_Clients.IdClient = Table_Tickets.IdClient
    where idtypeticket=2 and 
    bcloture is null and
    (ISNULL(Table_Adresses.IdCellule,Table_Clients.IdCellule)) = 4 
    order by IdCell