HELP !

[yangxiaochen]

Error: 
No match found for function signature TO_CHAR(<CHARACTER>)

BACKGROUND：
        I want to implement a function that can suffice for parsing and 
validating complex Oracle SQL. But I encountered some Oracle functions and 
keywords that are not supported during development, I don't know how to do it! 
What configuration do I need to do in Calcite to support all Oracle functions 
except custom functions? thank you very much

This is My Code :

public class Example1 {
    public static void main(String[] args) throws Exception {
        String sql = "SELECT a.ID, to_char(b.AGE ) FROM HDC_ODS.DEMO a LEFT 
JOIN HDC_ODS.DEMO1 b ON a.ID = b.ID";
        runProjectQueryWithLex(Lex.ORACLE, sql);
    }

    private static void runProjectQueryWithLex(Lex lex, String sql)
            throws SqlParseException, ValidationException, 
RelConversionException {
        SqlParser.Config javaLex = 
SqlParser.configBuilder().setLex(lex).build();
        Planner planner = getPlanner(null, javaLex, 
Programs.ofRules(Programs.RULE_SET));
        SqlNode sqlNode = planner.parse(sql);
        SqlNode validate = planner.validate(sqlNode);
        System.out.println(validate);
    }

    private static Planner getPlanner(List<RelTraitDef> traitDefs,
                                      SqlParser.Config parserConfig, Program... 
programs) {
        CalciteSchema calciteSchema = CalciteSchema.createRootSchema(true, 
true);
        SchemaPlus rootSchema = calciteSchema.plus();

        //final SchemaPlus rootSchema = Frameworks.createRootSchema(true);
        DataSource dataSource = 
JdbcSchema.dataSource("jdbc:oracle:thin:@//XXX:1521/ORCL?fun=oracle",
                "oracle.jdbc.driver.OracleDriver", “XXX", “XXX");
        final JdbcCatalogSchema schema =
                JdbcCatalogSchema.create(null, "", dataSource, "PUBLIC");
        final CalciteSchema rootSchema0 =
                CalciteSchema.createRootSchema(false, false, "", schema);

        final val schemaMap = rootSchema0.getSubSchemaMap();

        schemaMap.forEach((key, value) -> {
            rootSchema.add(key, value.schema);
        });

//        SqlOperatorTable opTab =
//                SqlLibraryOperatorTableFactory.INSTANCE.getOperatorTable(
//                        
EnumSet.of(SqlLibrary.ORACLE,SqlLibrary.STANDARD,SqlLibrary.SPATIAL));


        final FrameworkConfig config = Frameworks.newConfigBuilder()
                .parserConfig(parserConfig)
                .defaultSchema(rootSchema)
                .traitDefs(traitDefs)
                .programs(programs)
                .operatorTable(SqlStdOperatorTable.instance())
                .build();
        return Frameworks.getPlanner(config);
    }
}



This is My error:

Caused by: org.apache.calcite.sql.validate.SqlValidatorException: No match 
found for function signature TO_CHAR(<NUMERIC>)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at 
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
        at 
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
        at 
org.apache.calcite.runtime.Resources$ExInstWithCause.ex(Resources.java:505)
        at org.apache.calcite.runtime.Resources$ExInst.ex(Resources.java:599)
        ... 24 more