Word matching Django func

word_match.py

from django.db.models import Func


class WordMatch(Func):
    """Combination function which checks whether any non-empty words are in common.

    Roughly equivalent to bool(set(a.split()) & set(b.split())), but with MOAR sql.
    """
    sql_template = "array_length(array_remove(array(select unnest(string_to_array(%s, ' ')) intersect select unnest(string_to_array(%s, ' '))), ''), 1) >= 1"
    output_field = models.BooleanField()

    def as_sql(self, compiler, connection):
        first, second = self.source_expressions
        first_sql, first_params = compiler.compile(first)
        second_sql, second_params = compiler.compile(second)
        return self.sql_template % (first_sql, second_sql), first_params + second_params