Query Translation

Methodology

Summary of the workflow

• Validate SQL query
• Parse the SQL query into SQL clauses
• Translate parsed query

  Translation Process

  1. Process common table expressions
  2. Create streams: find all of the topics the query depends on (recursively) and create KsqlDB stream for it
     a. topic
     b. subquery
  3. Translate joins: Add a window clause to each join
  4. Translate functions:
     a. group_concat maps to collect_set or collect_list
     b. cast(_ as Date) maps to stringtodate or datetostring`
  5. Identifiers and aliases
     ex: transactions.storer replace with burroughs_transactions.storer
  6. Group by
     a. Replace integers with the field name
     b. Add SMT that extracts the group by from the record key