在查询中不使用空格和短表别名有什么好处吗？

Question

Do queries with no excessive spaces and small table aliases stress the MySQL server less or is the difference negligible?

SELECT my_table.a, my_table.b, my_table.c, my_table.d
FROM table_containing_data as my_table
WHERE my_table.a = 1 AND my_table.b = 1 AND my_table.c = 1 AND my_table.d = 1

vs.

SELECT t.a,t.b,t.c,t.d
FROM table_containing_data t
WHERE t.a=1 AND t.b=1 AND t.c=1 AND t.d=1

I am fully aware of the readability of each of them. This question is purely hypothetical. If the difference (when running queries like these hundreds of thousands of times a day) is significant, I might change how my query engine works.

Answer 1

Even for billions of queries, whitespace in your queries is not going to make the difference.

Databases cache queries and execution plans anyway, so if you end up sending the same query over and over again (why aren't you using prepared statements?) any decent database will not have to parse the whole thing again. Of course that only applies if you don't mix SQL and data in the same string.. which is usually done with MySQL. So here's another reason to use prepared statements!

Also, compared to actually retrieving data from the disk (which, by the way, should happen rarely if your database is not huge - you want LOTS of RAM in your database machines to have as much as possible in memory) any parsing etc. is negligible.