如何从两个表编写存储过程

Question

我有2张牌桌 - t1和t2。从t1开始，我想选择列order_no＆amp; order_Id在表格t2中有两列 - order_no和inv_no。

我想选择并显示表格order_no中的order_id和t1，以及表order_no中的inv_no是否有t2 ，我必须将其附加到order_no这样=＆gt; ord1002_inv045 ..

Answer 1

试试这个。

SELECT OrderNo = t1.order_no
    , OrderId = t1.order_Id
    , OrderNoWithInvoiceId = 
      CASE 
        WHEN t2.inv_no IS NULL 
            THEN t1.order_no 
        ELSE t1.order_no + '_' + t2.inv_no 
      END 
FROM t1 INNER JOIN t2 ON t1.order_no = t2.order_no