I know this isn't a specific bit of code or problem, but I am having trouble with a very similar issue to the person asking this (except theirs is for SQL Server): Combining INSERT INTO and WITH/CTE ...and I can't seem to find it out there on any SAP HANA help forums etc. so thought there may be an expert on here who can just give me a simple yes or no answer.
The SQL statement I am using contains multiple CTEs, but when I try to insert it tells me there is a Syntax error around the word INSERT. It is definitely laid out exactly the same as in the question I've linked above (spent hours checking), and I can post code samples if necessary but I simply want to know whether it is supported first! Thanks
Short answer: No, CTEs are not supported for INSERT/UPDATE statements.
Longer answer: SQLScript's INSERT/UPDATE commands are actually "borrowed" SQL commands as the documentation explains.
Checking the documentation for SQL INSERT we find that it supports a subquery as a source of values.
The subquery term is defined as part of the SQL SELECT statement. Checking the documentation for SELECT shows that <subquery> and <with_clause> are different, non-overlapping terms.
This means, that CTEs cannot be used in subqueries and therefore not be part of the subqueries used in INSERT/UPDATE commands.
You can, however, use SQLScript table variables in INSERT statements in your SQLScript blocks, which is very similar to CTEs:
DO BEGIN
te_a := SELECT 10, 'xyz' as VAL from dummy;
te_b := SELECT 20, 'abc' as VAL from dummy;
te_all := SELECT * from :te_a
UNION ALL SELECT * from :te_b;
INSERT INTO VALS
(SELECT * from :te_all);
END;