[ASTERIXDB-2441][COMP] Improve column alias handling in ORDERBY/LIMIT - user model changes: no - storage format changes: no - interface changes: no
Details: - Introduce LET clauses for column alias expressions instead of inlining them into ORDER BY/LIMIT clauses - Fix incorrect visitor used in SubstituteGroupbyExpressionWithVariableVisitor for rewriting LET clauses after GROUP BY
[ASTERIXDB-2366][TEST] Optimizer tests cleanup for SQL++ - user model changes: no - storage format changes: no - interface changes: no
Details: The current optimizerTest actually doesn't use the SQL++ test cases. The existed test cases for SQLPP also have various issues. This patch cleans part of the test cases which failed at variable names changes in the result query plan.