registerFunction( "char_length", new StandardSQLFunction( "char_length", StandardBasicTypes.INTEGER ) );
    registerFunction( "cos", new StandardJDBCEscapeFunction( "cos", StandardBasicTypes.DOUBLE ) );
    registerFunction( "cot", new StandardJDBCEscapeFunction( "cot", StandardBasicTypes.DOUBLE ) );
    registerFunction( "coalesce", new VarArgsSQLFunction( "coalesce(", ",", ")" ) );
    registerFunction( "concat", new VarArgsSQLFunction( StandardBasicTypes.STRING, "", "||", "" ) );
    registerFunction( "convert", new ConvertFunction() );
    registerFunction( "curdate", new StandardJDBCEscapeFunction( "curdate", StandardBasicTypes.DATE ) );
    registerFunction( "current_date", new NoArgSQLFunction( "current_date", StandardBasicTypes.DATE, false ) );
    registerFunction( "current_time", new NoArgSQLFunction( "current_time", StandardBasicTypes.TIME, false ) );
    registerFunction(
        "current_timestamp", new ConditionalParenthesisFunction( "current_timestamp", StandardBasicTypes.TIMESTAMP )