SQL SQL查询在内部联接期间连接两列
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SQL Query Concatenate two columns during Inner JOIN
提问by Niras
I have table A and table B with Table A having several columns including A1 and A2. Table B too has several columns. My query requires me to concatenate the values in A1 and A2 and then do an inner join on B1.
我有表 A 和表 B，表 A 有几列，包括 A1 和 A2。表 B 也有几列。我的查询要求我连接 A1 和 A2 中的值，然后在 B1 上进行内部连接。
Example:
例子：
Select *
From A
INNER JOIN B
ON CONCAT(A1,A2) = B1.
Apparently this is not how it should work. Can someone please give me a hand in this query?
显然这不是它应该如何工作。有人可以帮我解决这个问题吗？
Thanks.
谢谢。
回答by Andrey Gurinov
Try this:
尝试这个：
Select *
From A
INNER JOIN B
ON A1 + A2 = B1
回答by Pedro Ferreira
Table Geography
表地理
region_name store_name
East Boston
East New York
West Los Angeles
West San Diego
Example 1: For MySQL/Oracle:
示例 1：对于 MySQL/Oracle：
SELECT CONCAT(region_name,store_name) FROM Geography
WHERE store_name = 'Boston';
Result: 'EastBoston'
Example 2: For Oracle:
示例 2：对于 Oracle：
SELECT region_name || ' ' || store_name FROM Geography
WHERE store_name = 'Boston';
Result: 'East Boston'
Example 3: For SQL Server:
示例 3：对于 SQL Server：
SELECT region_name + ' ' + store_name FROM Geography
WHERE store_name = 'Boston';
Result: 'East Boston'
Starting from this, you can adapt to two tables without much issue. In doubt, use a virtual Table to make things more readable.
从这里开始，您可以适应两个表而没有太大问题。有疑问，使用虚拟表使事情更具可读性。
If in doubt check this other question which has been answered for more details.
如果有疑问，请查看已回答的其他问题以获取更多详细信息。
