On 2/8/16, Eric Hill <Eric.Hill at jmp.com> wrote: > Hey, > > It appears that LEFT and RIGHT are treated as reserved words by SQLite, so > my attempts to use sqlite3_create_function() to create my own LEFT and RIGHT > SQL functions have been unsuccessful (I'm using 3.8.11.1). Several > databases (SQL Server, MySQL) define their own LEFT and RIGHT functions for > performing sub-string functions, apparently without conflicting with LEFT > JOIN/RIGHT JOIN syntax. Is that just not possible for SQLite?
Not easily, it seems. There is a list of keywords that can fallback to be identifiers (https://www.sqlite.org/src/artifact/d7bff41d4?ln=220,233) if they cannot be parsed as their original keyword value. I tried adding JOIN_KW to that list. (JOIN_KW is a compound keyword that includes "LEFT", "RIGHT", "NATURAL", "CROSS", "FULL", "INNER", and "OUTER".) The result compiled, but lots of tests failed. I don't know if that is something that would be easy to fix or not. Even if it were possible to fix it, I am not in a big rush to do so. By allowing LEFT and RIGHT to be identifiers, we would be making a promise that they can be identifiers in all future versions of SQLite, which puts an additional constraint on future changes. I'm not sure this is worth it. -- D. Richard Hipp drh at sqlite.org
