If there are escape characters in identifiers (database name, table name, column name)
Identifier without ``: Error will be returned because identifier must be constituted of digits, ASCII characters or underscore and can't be started with digits
Identifier quoted with ``： Original content is kept, no escaping
If there are escape characters in values
The escape characters will be escaped as the above table. If the escape character doesn't match any supported one, the escape character "" will be ignored.
"%" and "_" are used as wildcards in like. \% and \_ should be used to represent literal "%" and "_" in like,. If \% and \_ are used out of like context, the evaluation result is "\%"and "\_", instead of "%" and "_".