public final FunctionNameContext functionName() throws RecognitionException {
		FunctionNameContext _localctx = new FunctionNameContext(_ctx, getState());
		enterRule(_localctx, 194, RULE_functionName);
		try {
			setState(1831);
			_errHandler.sync(this);
			switch ( getInterpreter().adaptivePredict(_input,248,_ctx) ) {
			case 1:
				enterOuterAlt(_localctx, 1);
				{
				setState(1827);
				qualifiedName();
				}
				break;
			case 2:
				enterOuterAlt(_localctx, 2);
				{
				setState(1828);
				match(FILTER);
				}
				break;
			case 3:
				enterOuterAlt(_localctx, 3);
				{
				setState(1829);
				match(LEFT);
				}
				break;
			case 4:
				enterOuterAlt(_localctx, 4);
				{
				setState(1830);
				match(RIGHT);
				}
				break;
			}
		}
		catch (RecognitionException re) {
			_localctx.exception = re;
			_errHandler.reportError(this, re);
			_errHandler.recover(this, re);
		}
		finally {
			exitRule();
		}
		return _localctx;
	}
When true, the behavior of keywords follows ANSI SQL standard.
amoro-format-mixed/amoro-mixed-spark/v3.5/amoro-mixed-spark-3.5/src/main/gen-antlr/org/apache/amoro/spark/sql/parser/MixedFormatSqlExtendParser.java