SQL Insert from Query
Sometimes my students find new errors that I’ve never seen. One student did that this week by including an ORDER BY clause in a subquery that feeds an INSERT statement. It raises an ORA-00907 exception, like:
ORA-00907: missing right parenthesis |
You can’t include a subquery with an ORDER BY clause because it generates an error. The reason is simple. A subquery can’t perform a sort operation inside a subquery. Here’s a quick demonstration:
DROP TABLE destination; CREATE TABLE destination ( destination_id NUMBER , destination_name VARCHAR2(20)); INSERT INTO destination ( SELECT 1,'Sample1' FROM dual UNION ALL SELECT 2,'Sample2' FROM dual ORDER BY 1 DESC ); |
If you remove the ORDER BY clause, the statement works without a problem. For example, here’s the working version:
INSERT INTO destination ( SELECT 1,'Sample1' FROM dual UNION ALL SELECT 2,'Sample2' FROM dual ); |
Alternatively, you can include an ORDER BY clause when you remove the parentheses from around the subquery. This is an example:
INSERT INTO destination SELECT 1,'Sample1' FROM dual UNION ALL SELECT 2,'Sample2' FROM dual ORDER BY 1 DESC; |
I hope this helps anybody who runs into the problem.
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