[CALCITE-7246] UNNEST in Spark should convert to EXPLODE/POSEXPLODE

[xiaochen-zhou]

See: [CALCITE-6469]

[dssysolyatin]

Add two separate operators in SqlLibraryOperators: one for explode and one for posexplode

And use it like:

if (call.getOperator() instanceof SqlUnnestOperator && ((SqlUnnestOperator) call.getOperator()).withOrdinality ) {
  SqlCall posexplodeCall = SqlLibraryOperators.POSEXPLODE
           .createCall(SqlParserPos.ZERO, call.getOperandList());
      super.unparseCall(writer, posexplodeCall, leftPrec, rightPrec);
} else {
  SqlCall explodeCall = SqlLibraryOperators.EXPLODE
           .createCall(SqlParserPos.ZERO, call.getOperandList());
      super.unparseCall(writer, explodeCall, leftPrec, rightPrec);

}

[mihaibudiu]

That is mostly useful if he wants to support it in input programs; here he wants to use it when outputting SQL.

[dssysolyatin]

Is the unparse logic different from the unparse logic of other function operators? If not, then there’s no need to create own mechanism to unparse a function call

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
94.1% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[dssysolyatin]

Also, you only covered the unparse part. It would be good to implement the parse part as well, so that explode/posexplode can be parsed and validated. Feel free to create a separate jira ticket for that if you don’t want to do it here

[mihaibudiu]

That is mostly useful if he wants to support it in input programs; here he wants to use it when outputting SQL.

[mihaibudiu]

this one is actually more tricky: I think the ordinality argument is swapped with the data argument in spark, So doing this won't work. You really have to rewrite the plan. You will have to validate this using a real program with data on spark.

[github-actions]

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