Delete Table1.* From Table1 Where Exists( Select 1 From Table2 Where Table2.Name = Table1.Name ) = True To expand on my answer, the official SQL specification does not provide for using Joins in action queries specifically because it can create ambiguous results. Thus, it is better (and Access is much happier) if you can avoid … Read more
Nope, you’d need to run multiple statements. Because you need to delete from two tables, consider creating a temp table of the matching ids: SELECT U.Id INTO #RecordsToDelete FROM Users U JOIN LinkingTable J ON U.Id = J.U_Id … And then delete from each of the tables: DELETE FROM Users WHERE Id IN (SELECT Id … Read more
You could query the dataset and then loop the selected rows to set them as delete. var rows = dt.Select(“col1 > 5”); foreach (var row in rows) { row.Delete(); } dt.AcceptChanges(); … and you could also create some extension methods to make it easier … myTable.Delete(“col1 > 5”); public static DataTable Delete(this DataTable table, string … Read more
You can use RETURNING clause: DELETE FROM table WHERE condition IS TRUE RETURNING *; After that you just have to check number of rows returned. You can streamline it with CTE: WITH deleted AS (DELETE FROM table WHERE condition IS TRUE RETURNING *) SELECT count(*) FROM deleted; This should return just the number of deleted … Read more
Due to the locking implementation issues, MySQL does not allow referencing the affected table with DELETE or UPDATE. You need to make a JOIN here instead: DELETE gc.* FROM guide_category AS gc LEFT JOIN guide AS g ON g.id_guide = gc.id_guide WHERE g.title IS NULL or just use a NOT IN: DELETE FROM guide_category AS … Read more
DELETE FROM table WHERE date < ‘2011-09-21 08:21:22’;
You could do a normal SQL truncate or delete command, using the DataContext.ExecuteCommand method: context.ExecuteCommand(“DELETE FROM Entity”); Or context.ExecuteCommand(“TRUNCATE TABLE Entity”); The way you are deleting is taking long because Linq to SQL generates a DELETE statement for each entity, there are other type-safe approaches to do batch deletes/updates, check the following articles: Batch Updates … Read more
If you delete an item from a collection, that collection has been changed and you can’t continue to enumerate through it. Instead, use a For loop, such as: for(int i = dtPerson.Rows.Count-1; i >= 0; i–) { DataRow dr = dtPerson.Rows[i]; if (dr[“name”] == “Joe”) dr.Delete(); } dtPerson.AcceptChanges(); Note that you are iterating in reverse … Read more