[CALCITE-2674] SqlIdentifier same name with built-in function but with escape character should be still resolved as an identifier

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.18.0
• Fix Version/s: 1.19.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Unassigned
• Reporter: Danny Chen
• Created: 15/Nov/18 10:10
• Updated: 25/Mar/19 00:10
• Resolved: 08/Mar/19 18:22

Description

Now If user defines table as schema below:

create table tt(
`current_time` int,
b int);

Then start a query: 

select `current_time` from tt;

Calcite parser will parse the current_time as a normal SqlIdentifier, then the SqlValidator will recognize it as a builtin function with below code snippet:

public static SqlCall makeCall(
    SqlOperatorTable opTab,
    SqlIdentifier id) {
  if (id.names.size() == 1) {
    final List<SqlOperator> list = new ArrayList<>();
    opTab.lookupOperatorOverloads(id, null, SqlSyntax.FUNCTION, list);
    for (SqlOperator operator : list) {
      if (operator.getSyntax() == SqlSyntax.FUNCTION_ID) {
        // Even though this looks like an identifier, it is a
        // actually a call to a function. Construct a fake
        // call to this function, so we can use the regular
        // operator validation.
        return new SqlBasicCall(
            operator,
            SqlNode.EMPTY_ARRAY,
            id.getParserPosition(),
            true,
            null);
      }
    }
  }
  return null;
}

While i tried MYSQL and such query can work properly, so is this a bug ?

Cause if the matched function's return type is same with the column, then the query will output wrong results.

 

Issue Links

• relates to: CALCITE-2721 Support parsing of DOT + MEMBER_FUNCTION
• links to: GitHub Pull Request #958