Besides the chain statements such as CRUD and query, the rest of a UQL statement are clauses begin with keywords. Clauses can compute and process the results of the preceding statements, and pass the new results to subsequent statements or return the results. This chapter will introduce the following clause keywords:
- GROUP BY
- ORDER BY
- UNION / UNION ALL V4.1
The query results of UQL are passed between different chain statements and clauses in the form of data stream, and eventually returned to user.