SQL Difference Between Using = and IN

Question

What is the difference between using the following statements in a WHERE clause in SQL?

WHERE STUDENTID=7

or

WHERE STUDENTID IN (7)

Is there a recommended / optimal choice?

Answer 1

Use IN if you are doing multiple or, for example,

Where StudentID = 7 or StudentID = 6 or StudentID = 5

Will be

Where StudentID IN (5,6,7)

Otherwise, just use =

Answer 2

There is no functional difference, the result is the same.

The performance will be different if the database processes them differently, but it is likely that the database will recognize that you are using exactly one value in the expression inand actually make up an execution plan as if it were the first.

, , , , in.

Answer 3

IN - :

( StudentID = 7 or StudentID = 6 or ... )

NULL .

Answer 4

, .., , , SQL, Oracle OPTIMIZER , -write, . - , , . , .

IN -

StudentID = 7 StudentID = 6 StudentID = 5

OR, IN.

Answer 5

, . , IN.

:

a, b c .

=, :

Select * from table_name where name = 'a' or name = 'b' or name = 'c' 

IN

Select * from table_name where name in('a','b','c')