What do you do with double quotes in the PDO of PHP, and why this statement can be executed by

Find a lightweight database class Medoo, feel good, but when used to find a very strange problem
When using MySQL, he assembled SQL table names, field names in double quotation marks, so that the resulting statement cannot be executed directly

Mysql> select * from "Dd_xq_user_info" WHERE "uid" = ' 1 ' and ' status ' = ' 1 ' ORDER by ' id ' LIMIT 1; Error 1064 (42000): You have a error in your SQL syntax; Check the manual-corresponds to your MySQL server version for the right syntax-use "" Dd_xq_user_info "WHERE" UID "= ' 1 ' and" status "= ' 1 ' ORDER by" id "LIMIT 1 ' on line 1

However, the execution of this statement with PDO is successful, and there is no error, may I ask what this is all about? What does PDO do?

Reply to discussion (solution)

It's impossible!
Stick out your real code.

Just read through the next Medoo code https://github.com/catfan/Medoo/blob/master/medoo.php
Found executing a statement when connecting to the database
SET sql_mode=ansi_quotes
found that the function of this pattern is to change the double quotation mark to the inverted quotation mark

Ansi_quotes ' "' is treated as the identifier quotation mark (' ' ' quotation mark character), not as the quotation mark character of the string. In ANSI mode, you can still use "' to refer to identifiers. When Ansi_quotes is enabled, you cannot use double quotation marks to reference a string because it is interpreted as a qualifier.

This explains why the above statement can be executed
Can't think of any other problems for the time being.

The default value for Sql_mode is Strict_trans_tables,no_auto_create_user,no_engine_substitution
After the change to ansi_quotes, if there is no other operation, nature will not have an impact

This is the function of MySQL, not the PDO

This is the function of MySQL, not the PDO

Yes, I thought PDO had this function.
By the way I wish the Dragon Boat Festival health, thanks for the holiday also help answer

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