如何检查数据库列是否存在，然后添加选择查询

Question

如何检查数据库列是否存在，然后添加选择查询IF EXISTS(t2.DateOfBill){t2.DateOfBill}else{t2.BillDate}或IF EXISTS(t2.AreaId){t2.AreaId}。我在下面提到了示例查询。请帮忙。

Table
ID ShopID OrderID   
3  350    001414    
4  351    001415

Table2
ID TableID ShopId DateOfBill AreaID
1  3        350   2016/01/03  250

Table3
ID TableID ShopId BillDate 
1  4        351   2016/01/03




SELECT t1.id, t1.shopID,
IF EXISTS(t2.DateOfBill){t2.DateOfBill}else{t2.BillDate}, 
IF EXISTS(t2.AreaId){t2.AreaId} 
FROM TABLE t1 
INNER JOIN TABLE2 t2 ON t2.OrderID = t1.OrderID AND t2.shopID = t1.shopID  
WHERE t1.OrderID IN ('001414') AND t1.shopID = 350 AND t1.Status = 'Open';


SELECT t1.id, t1.shopID,
IF EXISTS(t2.DateOfBill){t2.DateOfBill}else{t2.BillDate}, 
IF EXISTS(t2.AreaId){t2.AreaId} 
FROM TABLE t1 
INNER JOIN TABLE3 t2 ON t2.OrderID = t1.OrderID AND t2.shopID = t1.shopID  
WHERE t1.OrderID IN ('001414') AND t1.shopID = 350 AND t1.Status = 'Open';

我想在单个查询中管理所有事情。