[CALCITE-7814] Support the SQL-standard CYCLE clause in recursive CTEs

[vldpyatkov]

CALCITE-7814
The implemented CYCLE syntax

cycle_clause ::= CYCLE key_column { ',' key_column }
                 SET mark_column
                 [ TO cycle_value DEFAULT non_cycle_value ]
                 USING path_column

Explicit mark values must be distinct, non-null Boolean literals or compatible single-character string literals. Omitting TO ... DEFAULT ... uses TRUE and FALSE, respectively.
The clause is represented by SqlCycleClause on SqlWithItem. During validation, CycleRewriter rewrites the query to maintain the cycle mark and an ARRAY<ROW<...>> path. A row that closes a cycle is returned but is not expanded further.

During implementation, I found an issue with comparing ARRAY<ROW<...>> values and fixed the comparer to compare their elements by content. This is needed for correct duplicate elimination when the result includes a cycle path column.

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
89.6% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud