在数据集中重复列名

Question

I have in database 2 identical tables - let's say ARTICLE and ARTICLE_BACKUP. They have different records but all the columns are the same.

I can join them and read into dataset in C#

SELECT * from ARTICLE A INNER JOIN ARTICLE_BACKUP A2 ON A.ID=A2.ID

In SQL when working on joined tables you use table name and column name like

ARTICLE_BACKUP.NAME

so you will never mix columns with identical names from different tables.

When you read it to dataset, the table names are gone however. ARTICLE.NAME will be called just NAME and ARTICLE_BACKUP.NAME will be in most cases called NAME1 - "1" is added to the name,

But what if NAME1 column already existed in sql query like:

SELECT A.NAME,A.NAME1,A.NAME11, B.NAME,B.NAME1,B.NAME11, C.NAME,C.NAME1,C.NAME11, FROM A INNER JOIN B ON A.ID=B.ID INNER JOIN C on A.ID=C.ID

what will be the names of columns in dataset for the columns from B and C tables ?

I can check it but could anybody say the rule?

Is there any 100% working way when having a column in sql query to know its name in dataset?

Answer 1

"Is there any 100% working way when having a column in sql query to know its name in dataset?"

Yes, don't use select * . Manually type out the columns you want and you can alias them.

Example

SELECT A.Column1 as AColumn1, A2.Column1 as A2Column1 from ARTICLE A INNER JOIN ARTICLE_BACKUP A2 ON A.ID=A2.ID

Then in your C# code you would access the columns via their aliased names.