Hi, We have an usecase where we need to just send back optimized query as SQL, without executing it. So we needed an utility to convert RelNode back to SQL, and found most of the logic to be in JDBCRel. As we needed it for non JDBC source, we created an utility to do so: https://github.com/amoghmargoor/incubator-calcite/blob/NEZ-52/core/src/main/java/org/apache/calcite/rel/rel2sql/RelToSqlConverter.java
Utility is almost completely copy-pasted from JDBCRels with few fixes from our side to make it work. If such utility will be useful in Calcite then let us know, we can plan raising PRs with required UTs. Regards, Amogh
