CODEWITHSUNDEEP
mysqldatabase
Ishan Trivedi
Ishan Trivedi

Reputation: 125

Where does user-defined variables will be stored into mysql 8.0.16?

Suppose I defined two variables in mysql as follows:

SET @STUDENT_NAME = 'ABCD';
SET @STUDENT_AGE = 25;

Now, When I'm was selecting these two variables value using following: 

SELECT @STUDENT_NAME, @STUDENT_AGE;

It was perfectly showing corresponding values, even if I switched the database.

But when I restarted mysql and tried to select these values, It was showing null values of these variables, So where would it be stored actually when I had set values?

Upvotes: 0

Views: 82

Answers (1)

Marc Alff
Marc Alff

Reputation: 8395

Per the manual (emphasis mine):

https://dev.mysql.com/doc/refman/8.0/en/user-variables.html

User-defined variables are session specific. A user variable defined by one client cannot be seen or used by other clients. (Exception: A user with access to the Performance Schema user_variables_by_thread table can see all user variables for all sessions.) All variables for a given client session are automatically freed when that client exits.

Upvotes: 1

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