What makes the big difference between a backtick and an apostrophe?

Question

What is the reason that the following two queries give wildly different results?

MariaDB [mydatabase]> SELECT COUNT(DISTINCT(`price`)) FROM `products`; --         


        

Answer 1

Please find MariaDB's documentation about identifier names and string literals:

https://mariadb.com/kb/en/mariadb/identifier-names/

https://mariadb.com/kb/en/mariadb/string-literals/

Backquotes always quote identifier namens. Single quotes always quote string literals.

Identifier names get replaced by their value, string literals don't:

SELECT `price`, 'price' FROM products;
+-------+-------+
|     1 | price |
|     1 | price |
|     2 | price |
|     3 | price |
|     3 | price |
+-------+-------+