How to Escape Special Characters for Accurate Pattern Matching in PostgreSQL?

Escaping Strings for Pattern Matching in PostgreSQL

To accurately match patterns in PostgreSQL where the user-supplied string may contain special pattern characters like %, consider escaping these characters to ensure precise matches. Alternatively, the application can handle the escaping process.

In PostgreSQL, characters like % and _ have to be quoted using the , but this can be customized with the ESCAPE clause. To match the character literally, it must be quoted twice.

For instance, to match the pattern 'john%node1^node2.uucp@' with ^ as the escape character, use the following query:

... WHERE field LIKE 'john^%node1^^node2.uucp@%' ESCAPE '^'

However, when standard_conforming_strings is disabled (PG 9.1 has it enabled by default), is utilized for other purposes. Additionally, client-side quoting may be necessary in injection scenarios.

For generic handling in Go, considering both standard_conforming_strings and alternative quote characters, the following query can be used:

db.Query("SELECT * from USERS where name like replace(replace(replace(,'^','^^'),'%','^%'),'_','^_') ||'%' ESCAPE '^'",
     variable_user_input);

This handles the escaping and replacement of special characters on the server-side, preventing SQL injection and ensuring accurate pattern matching.

The above is the detailed content of How to Escape Special Characters for Accurate Pattern Matching in PostgreSQL?. For more information, please follow other related articles on the PHP Chinese website!