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I try to found some information about limitations of used a SELECT using FOR READ ONLY on subqueries (Ultralite), everytime i try this an error occurs: Syntax error near 'FOR' [SQL Offset: 1735] SQLCODE=-131, ODB 3 STATE="4200" Select example: SELECT COUNT(*) as groupCount FROM (SELECT name FROM table FOR READ ONLY ) AS DS (name) This really don't work? why? |
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Short answer: Subqueries can't be anything other than read-only, so FOR READ ONLY is superfluous. The FOR READ ONLY clause is only allowed in an outer SELECT statement, not a subquery, because only a SELECT statement can be used to fetch and update rows in a cursor... in other words, FOR UPDATE and hence FOR READ ONLY make no sense on a subquery... so you'll get the same SQLCODE -131 if you run your query on a SQL Anywhere server. Here are a couple of examples... Could not execute statement.
Syntax error near 'READ' on line 5
SQLCODE=-131, ODBC 3 State="42000"
Line 1, column 1
SELECT *
FROM dummy
WHERE dummy_col IN ( SELECT dummy_col
FROM dummy
FOR READ ONLY )
-----
Could not execute statement.
Syntax error near 'UPDATE' on line 5
SQLCODE=-131, ODBC 3 State="42000"
Line 1, column 1
SELECT *
FROM dummy
WHERE dummy_col IN ( SELECT dummy_col
FROM dummy
FOR UPDATE )
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