Straight quotes can be used like backticks around aliases IN SOME CASES (as of 5.0.15, at least). Observe:<\/p>\n
These three queries produce identical output:<\/p>\n Likewise, these three produce identical output:<\/p>\n Same with these nine:<\/p>\n Obviously, these two are different:<\/p>\n As are any queries that compare a straight-quoted value to some other field:<\/p>\n Please refrain from using this knowledge outside of stumping your colleagues with arcane MySQL trivia. I shudder to think what misfortune awaits the developer who deliberately uses straight quotes in this fashion.<\/p>\nCREATE TABLE myTable (id int, someData int);
\nINSERT INTO myTable VALUES (1, 1), (1, 2), (1, 3), (2, 1), (2, 2);<\/code><\/p>\nSELECT * FROM myTable GROUP BY id;
\nSELECT * FROM myTable GROUP BY `id`;
\nSELECT * FROM myTable GROUP BY 'id';<\/code>
\n<\/p>\nSELECT id AS theId FROM myTable;
\nSELECT id AS `theId` FROM myTable;
\nSELECT id AS 'theId' FROM myTable;<\/code><\/p>\nSELECT id AS theId FROM myTable GROUP BY theId;
\nSELECT id AS theId FROM myTable GROUP BY `theId`;
\nSELECT id AS theId FROM myTable GROUP BY 'theId';
\nSELECT id AS `theId` FROM myTable GROUP BY theId;
\nSELECT id AS `theId` FROM myTable GROUP BY `theId`;
\nSELECT id AS `theId` FROM myTable GROUP BY 'theId';
\nSELECT id AS 'theId' FROM myTable GROUP BY theId;
\nSELECT id AS 'theId' FROM myTable GROUP BY `theId`;
\nSELECT id AS 'theId' FROM myTable GROUP BY 'theId';<\/code><\/p>\nSELECT DISTINCT id FROM myTable; -- produces '1' and '2'
\nSELECT DISTINCT 'id' FROM myTable; -- produces 'id'<\/code><\/p>\nSELECT id AS theId FROM myTable GROUP BY theId = 1; -- two rows in result
\nSELECT id AS theId FROM myTable GROUP BY 'theId' = 1; -- one row in result<\/code><\/p>\n