Database show me everything okay but doesn't exist such column of value in table

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I have a query where I update a record where id = 0; however 0 value not exists in my table A. and sql show me that 0 rows affected What is the meaning of this?

What I have tried:

I think it occurs when query syntax true but doesn't matter some value exist or not.

Posted 22-Oct-22 0:07am

vor_zakon_developer

Updated 22-Oct-22 4:27am

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Richard MacCutchan · Answer 1 · 2022-10-22T00:36:00

Solution 1

Quote:
sql show me that 0 rows affected What is the meaning of this?

It means exactly what it says: your SQL command did nothing because there was no row with id=0, so zero rows were changed.

Posted 22-Oct-22 0:36am

Richard MacCutchan

Dave Kreskowiak · Answer 2 · 2022-10-22T04:27:00

Solution 2

Quote:
I have a query where I update a record where id = 0; however 0 value not exists in my table A.

You don't see a problem with this?

If you don't see the problem, you really need to go back to the very basics of learning relational databases and SQL.

Posted 22-Oct-22 4:27am

Dave Kreskowiak

Comments

vor_zakon_developer 22-Oct-22 15:02pm

@Date Kreskowiak I watched many tutorials about rdbms or sql there are not any concept that teach us in this topic. to better understand I ask the question because. so what? as I understand you didn't understand as well didn't you?

Dave Kreskowiak 22-Oct-22 15:09pm

Actually, I understood it quite well at the beginning, and yes, every tutorial DOES teach this concept. It's the entire basis of what and how relational databases work.

ANY documentation and tutorial on updating a row in a table will always refer to WHERE clauses that use an ID, or Primary Key, to identify and work with specific rows in a table.