Structured Query Language (SQL) is the standard language on relational databases (RDB). SQL is a universal and useful RDB language.
Most SQL standards are supported.
The main incompatible items of DWS are as follows:
- Transaction isolation levels Serializable and Repeatable Read are not supported.
- Unique constraints take effect only within DNs.
- The PREPARE statement does not support complex queries.
- The row-level trigger and COPY cannot be used together.
- COPY TO cannot use tables distributed in Replication mode.
- CREATE TABLE AS EXECUTE cannot be used.
- WHERE CURRENT OF cannot be used.
- A cursor does not support MOVE BACKWARD.
- FOREIGN DATA WRAPPER cannot be used.
- LISTEN, UNLISTEN, and NOTIFY are supported only on CNs.
- SECURITY LABEL cannot be used.
- The distribution columns in a table cannot be updated.
For details about error information during SQL execution, see Error Code Reference.