SQL Queries and Subqueries
GaussDB is compatible with SQL queries and subqueries except hierarchical queries.
| No. | Oracle Database | GaussDB | Difference |
|---|---|---|---|
| 1 | Creating simple queries | Supported. | - |
| 2 | Hierarchical queries | Not supported. | - |
| 3 | UNION [ALL], INTERSECT, MINUS | Supported. | - |
| 4 | Sorting query results | Supported, with differences. | If the GaussDB query does not contain groups and the target column contains both an aggregate function and a set returning function, the sorting of the set returning function column is not ignored. |
| 5 | Joins | Supported, with differences. | GaussDB supports only the same join types as Oracle Database, such as left/right, self, natural, and full outer join. Join optimization methods such as IN-MEMORY JOIN GROUPS are not supported. |
| 6 | Using subqueries | Supported. | - |
| 7 | Unnesting of nested subqueries | Supported, with differences. | HASH_AJ or MERGE_AJ cannot be explicitly specified in GaussDB. |
| 8 | Distributed queries | Supported, with differences. | GaussDB requires explicit database link query. |
| 9 | Aggregate function nesting | Supported. | - |
Feedback
Was this page helpful?
Provide feedbackThank you very much for your feedback. We will continue working to improve the documentation.
