[feature] Support sql mode NO_BACKSLASH_ESCAPES

[mirromutth]

Is your feature request related to a problem? Please describe.

When sql_mode contains NO_BACKSLASH_ESCAPES, MySQL server does not allow the use of \ as an escape character. In this mode, we should not use \ to escape strings.

For example:

CREATE TABLE escape_test(id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, value VARCHAR(50) NOT NULL);

INSERT INTO escape_test (`value`) VALUES ('my\ndata');

SELECT * FROM escape_test WHERE value = 'my
data'; -- 1 row
SELECT * FROM escape_test WHERE value = 'my\ndata'; -- 1 row

SET SESSION sql_mode = 'NO_BACKSLASH_ESCAPES';

SELECT * FROM escape_test WHERE value = 'my
data'; -- 1 row
SELECT * FROM escape_test WHERE value = 'my\ndata'; -- 0 row

Describe the solution you'd like

• Make ServerStatuses.NO_BACKSLASH_ESCAPES available
• If NO_BACKSLASH_ESCAPES is set, disable escape
• For the innodb_lock_wait_timeout, use SHOW VARIABLES LIKE 'innodb\_lock\_wait\_timeout' instead of SHOW VARIABLES LIKE 'innodb\\_lock\\_wait\\_timeout'