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5 Σεπ 2008 · Delete all but top n from database table in MS SQL using OFFSET command. WITH CTE AS ( SELECT ID FROM dbo.TableName ORDER BY ID DESC OFFSET 11 ROWS ) DELETE CTE; Replace ID with column by which you want to sort. Replace number after OFFSET with number of rows which you want to keep.
27 Απρ 2018 · The trick is making a view that contains the top, say, 1,000 rows that you want to delete: Transact-SQL CREATE VIEW dbo.Comments_ToBeDeleted AS SELECT TOP 1000 * FROM dbo.Comments ORDER BY CreationDate; GO
The SQL Server (Transact-SQL) DELETE TOP statement is used to delete records from a table in SQL Server and limit the number of records deleted based on a fixed value or percentage. Syntax. The syntax for the DELETE TOP statement in SQL Server (Transact-SQL) is: DELETE TOP (top_value) [ PERCENT ] . FROM table. [WHERE conditions];
15 Σεπ 2022 · Assume you have to delete 10 records in a 200’000’000 records table, you have to perform an ORDER BY on the whole table and this leads to catastrophic performance (and a complete lock of the table in SQLserver).
The question boil down would the where clause matter if I always deleting TOP 1000. The answer is that it does. The reason may be because there are simultaneous insert during the delete, and the insert must be blocking the delete due to page lock.
You can break it up into chunks - delete in a loop; each delete iteration it's own transaction and then clearing the log at the end of each loop iteration. Finding the optimal chunk size will take some testing.
MySQL supports the LIMIT clause to select a limited number of records, while Oracle uses FETCH FIRST n ROWS ONLY and ROWNUM. SQL Server / MS Access Syntax: SELECT TOP number | percent column_name(s)
