Question

我需要区分两个表。我需要比较Product，Qty＆amp;来自两个表的价格列，并说明其新记录或我需要提及哪个列值已更改。

示例表A

Product | Qty | Price | Comments

A          20    500     xyz
B          50    200     xyz
C          90    100     abc

示例表B

Product | Qty | Price | Comments

A          20    500     sd
B          70    200     cv
C          90    200     wsd
D          50    500     xyz

目前我正在使用Expect，它会提供所有新的/不匹配的行。

select Product,Qty,Price 
from TableB 
except 
select Product,Qty,Price 
from TableA

Product | Qty | Price 
B          70    200   
C          90    200   
D          50    500

但我需要结果集如下

Product |  Result

B          Updated Qty
C          Updated Price
D          New

Answer 1

您可以使用LEFT JOIN：

执行此操作

SELECT  b.Product,
        b.Qty,
        b.Price,
        Result = CASE WHEN a.product IS NULL THEN 'New'
                    ELSE 'Updated: ' + 
                        STUFF(  CASE WHEN a.Qty != b.Qty THEN ',Qty' ELSE '' END + 
                                CASE WHEN a.Price != b.Price THEN ',Price' ELSE '' END,
                            1, 1, '')
                END
FROM    TableB b    
        LEFT JOIN TableA a
            ON a.Product = b.Product
WHERE   a.Product IS NULL
OR      a.Qty != b.Qty
OR      a.Price != b.Price;

<强> Example on SQL Fiddle

Answer 2

不是最简洁的方法，但可读且可能有效：

SELECT B.Product,
       Result = 'Updated Qty'
FROM TableB B 
LEFT OUTER JOIN TableA A
    ON B.Product = A.Product 
WHERE A.Product IS NOT NULL 
AND A.Qty <> B.Qty
AND A.Price = B.Price

UNION ALL

SELECT B.Product,
       Result = 'Updated Price'
FROM TableB B 
LEFT OUTER JOIN TableA A
    ON B.Product = A.Product 
WHERE A.Product IS NOT NULL 
AND A.Price <> B.Price
AND A.Qty = B.Qty

UNION ALL

SELECT B.Product,
       Result = 'Updated Qty and Price'
FROM TableB B 
LEFT OUTER JOIN TableA A
    ON B.Product = A.Product 
WHERE A.Product IS NOT NULL 
AND A.Price <> B.Price
AND A.Qty <> B.Qty

UNION ALL

SELECT B.Product,
       Result = 'New'
FROM TableB B 
LEFT OUTER JOIN TableA A
    ON B.Product = A.Product 
WHERE A.Product IS NULL

Demo

如果您需要订购结果，则必须在here等外部查询中执行此操作。

SQL Server 2008比较同一数据库中的两个表，并更改get列

2 个答案: