[FLINK-32363] calcite 1.21 supports type coercion but flink don't enable it in validate

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Duplicate
• Assignee: Unassigned
• Reporter: Jacky Lau
• Created: 16/Jun/23 03:19
• Updated: 16/Jun/23 07:23
• Resolved: 16/Jun/23 06:45

Description

1) calcite 1.21 supports type coercion and enabled default while flink disabled

2) spark /mysql can run it 

3) although, we can make it run by select count(distinct `if`(1>5, 'x', cast(null as varchar)));

i think we should enable it or offers a config to enable it

 

Flink SQL> select count(distinct `if`(1>5, 'x', null));
[ERROR] Could not execute SQL statement. Reason:
org.apache.calcite.sql.validate.SqlValidatorException: Illegal use of 'NULL'

// it can run in spark
spark-sql (default)> select count(distinct `if`(1>5, 'x', null)); 
0

 

private def createSqlValidator(catalogReader: CalciteCatalogReader) = {
  val validator = new FlinkCalciteSqlValidator(
    operatorTable,
    catalogReader,
    typeFactory,
    SqlValidator.Config.DEFAULT
      .withIdentifierExpansion(true)
      .withDefaultNullCollation(FlinkPlannerImpl.defaultNullCollation)
      .withTypeCoercionEnabled(false)
  ) // Disable implicit type coercion for now.
  validator
} 

Issue Links

• duplicates: FLINK-17484 [FLIP-154] Enable type coercion