Question

我有一张具有以下结构的表

Table1
itemName, codeA, codeB, codeC, codeD

Table2
purchaseDate, shopCode, itemCode

表2 itemCode是对应于商店代码的代码

例如，我有以下项目：

Table1
Item A, A1, B1, C1, D1
Item B, A2, B2, C2, D2

Table2 
2012-03-27 11:00:00, 1, A1
2012-03-27 11:00:00, 2, B2
2012-03-27 13:00:00, 4, D1

在表2中，shopCode（1-4）等于表1（codeA-codeD），如何选择table2记录和项目名称？

Answer 1

SELECT
    t1.itemName,
    t2.purchaseDate,
    t2.shopCode,
    t2.itemCode
FROM
    table1 t1 JOIN
    table2 t2 ON t2.itemCode IN (t1.codeA, t1.codeB, t1.codeC, t1.codeD)

Answer 2

SELECT t2.*, t1.itemName
from Table2 t2
INNER JOIN Table1 t1 ON
  (t2.shopCode = 1 AND t2.itemCode = t1.codeA) OR
  (t2.shopCode = 2 AND t2.itemCode = t1.codeB) OR
  (t2.shopCode = 3 AND t2.itemCode = t1.codeC) OR
  (t2.shopCode = 4 AND t2.itemCode = t1.codeD);

在这里演示 - http://sqlfiddle.com/#!2/773a4/2

从给定条件中选择不是列名的列

2 个答案: