I have a text field to accept regular expressions from the UI. For these regular expressions, I have a search capability and want to do a search. I am using prepared statements and the DB is mysql. When I do a search on '%', I only want search regex starting with '%'. But, since '%' is wildcard in mysql, I get all the regex in the search. How to escape it.
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回答1:
Just use a backslash before the character, as shown in the MySQL documentation section 9.1:
\0 An ASCII NUL (0x00) character. \' A single quote ("'") character. \" A double quote (""") character. \b A backspace character. \n A newline (linefeed) character. \r A carriage return character. \t A tab character. \Z ASCII 26 (Control+Z). See note following the table. \\ A backslash ("\") character. \% A "%" character. See note following the table. \_ A "_" character. See note following the table. Note (from the MySQL documentation):
If you use "\%" or "\_" outside of pattern-matching contexts, they evaluate to the strings "\%" and "\_", not to "%" and "_".
回答2:
If you are using PHP, you may escape %, _ and characters using this code:
$escaped = addcslashes($str, "%_");The \ (backslash) and quotes you of course must also escape (as always! To prevent SQL injection), e.g. by mysql_real_escape_string().