Enroll (sno, cno, grade)
Select sno from enroll the where cno='c1'
Why the query results only column, the column name under no data?

CodePudding user response:

My test is found out there is your content didn't fill in the corresponding field

CodePudding user response:

You don't add conditions can you check the data?
Is likely to be cno there are some invisible characters,
In addition, look at your table structure, define a nchar fixed length (10),