Firebird recursive query3/13/2023 You cannot use ROWS together with FIRST and/or SKIP in a single SELECT statement, but is it valid to use one form in the top-level statement and the other in subselects, or to use the two syntaxes (You can often “ fake it” though, by supplying a second argument that you know to be bigger than the number of rows in the set.) The SQL-compliant ROWS syntax obviates the need for FIRST and SKIP, except in one case: a SKIP without FIRST, which returns the entire remainder of the set after skipping a given number of rows. If m lies within the set but n doesn't, the rows from m to the end of the set are returned. If m > the total number of rows in the dataset, an empty set is returned. The subquery also contains the GROUP BY item flds.rdb$relation_name, but that's not immediately obvious because in this case the GROUP BY clause uses the column number. Max(flds.rdb$field_position) + 1 as "Last fieldpos" It uses the aggregate function MAX in a subquery.įlds2.rdb$relation_name = flds.rdb$relation_nameĪnd flds2.rdb$field_position = max(flds.rdb$field_position) The next query shows the last field from each table and and its 1-based position. Where rels.rdb$relation_name = flds.rdb$relation_name The subquery refers to flds.rdb$relation_name, which is also a GROUP BY item:įlds.rdb$relation_name as "Relation name", This query returns each table's ID and field count.
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |