Select * and select all fields are written. Speed comparison !, Select Field

Select * and select all fields are written. Speed comparison !, Select Field

From a very early time, I heard the teacher say that select * from table is much slower than select a, B, c, and d from table. It has never been tested for three years. Today, we are not able to perform a test. We don't know what to expect.

Of course, the following is purely a test and is not applied to actual projects. If you have any comments or suggestions, please advise.

 

Times	* Number query	Field Query
First time
Second
Third time

 

The test code is as follows: