def _compile_union(self, union):
        if union['all']:
            joiner = ' UNION ALL '
        else:
            joiner = ' UNION '

        return '%s(%s)' % (joiner, union['query'].to_sql())
Compile a single union statement
dataset/ETHPy150Open sdispater/orator/orator/query/grammars/mysql_grammar.py/MySQLQueryGrammar._compile_union