[CALCITE-5179] In RelToSqlConverter, AssertionError for values with more than two items when SqlDialect#supportsAliasedValues is false

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.31.0
• Labels: pull-request-available
• Assignee: Jiajun Xie
• Reporter: Steven Talbot
• Created: 03/Jun/22 22:29
• Updated: 03/Aug/22 16:21
• Resolved: 09/Jun/22 14:38

Description

The code at https://github.com/apache/calcite/blob/4b349032c17b95735b12593a65f7027d54d8b8b6/core/src/main/java/org/apache/calcite/rel/rel2sql/RelToSqlConverter.java#L802-L803 creates a UNION ALL with an arbitrary number of operands, but the UNION_ALL operator is a SqlSetOperator which is a "SqlBinaryOperator" (Binary syntax). So that generates an assertion error when it unparses more than two values at https://github.com/apache/calcite/blob/4b349032c17b95735b12593a65f7027d54d8b8b6/core/src/main/java/org/apache/calcite/sql/SqlUtil.java#L426

 

I don't think I've done anything nonstandard, other than use a dialect with that flag set to false. To reproduce, create a values RelNode with more than two items, convert it with RelToSqlConverter with a dialect using supportsAliasedValues() = false (like Redshift), and attempt to unparse the resulting SqlNode.

Issue Links

• links to: GitHub Pull Request #2827