2013年7月9日 · Your second DELETE query was nearly correct. Just be sure to put the table name (or an alias) between DELETE and FROM to specify which table you are deleting from. This is simpler than using a nested SELECT statement like in the other answers. Corrected Query (option 1: using full table name):

2016年11月28日 · Said that, you should start to delete all ProjectSchemes without a corresponding Project. These are ProjectSchemes with an id of NULL or an id which does not exists in the Projects Table: DELETE ProjectSchemes WHERE (Project_Id is NULL) OR (NOT EXISTS (SELECT * FROM Projects WHERE Projects.Project_Id = ProjectSchemes.Project_Id))

delete dup row keep one table has duplicate rows and may be some rows have no duplicate rows then it keep one rows if have duplicate or single in a table. table has two column id and name if we have to remove duplicate name from table and keep one. Its Work Fine at …

2015年4月16日 · The canonical T-SQL (SqlServer) answer is to use a DELETE with JOIN as such. DELETE o FROM Orders o INNER JOIN Customers c ON o.CustomerId = c.CustomerId WHERE c.FirstName = 'sklivvz' This will delete all orders which have a …

2013年5月8日 · DELETE FROM [table] where id in (select max(id) from [table] group by id, col2, col3 having count(id) > 1) Be sure to test your results first and having a limiting condition in your "having" clausule. With such a huge delete query you might want to update your database first.

2019年3月13日 · You should do a small pl/sql block using a cursor for loop and delete the rows you don't want to keep. For instance: declare prev_var my_table.var1%TYPE; begin for t in (select var1 from my_table order by var 1) LOOP -- if previous var equal current var, delete the row, else keep on going. end loop; end;

2014年10月24日 · I am looking for a query that is able to delete all rows from a table in a database where timestamp is older than the current date/time or current timestamp. Would really appreciate some help out here urgently! Here's the query I am using but as I thought it ain't working: delete from events where timestamp<CURRENT_TIMESTAMP{);

I am trying to run a SQL query to delete rows with id's 163 to 265 in a table. I tried this to delete less number of rows. DELETE FROM `table` WHERE id IN (264, 265) But when it comes to delete 100's of rows at a time, Is there any query similar to above method I am also trying to use this kind of query but failed to execute it

To add "Cascade delete" to an existing foreign key in SQL Server Management Studio: First, select your Foreign Key, and open its "DROP And CREATE To.." in a new Query window. Then, just add ON DELETE CASCADE to the ADD CONSTRAINT command: And hit the "Execute" button to run this query.

If you specify your fill requirements, someone can probably suggest a join instead of what I suspect you will do (pull the value from the table into a variable in one step, and then a query using the variable in a second step). –