Before I go any further: Yes, I know that cursors perform poorly compared with set-based operations.In this particular case I'm running a cursor on a temporary table of 100 or so records, and that temporary table will always be fairly small, so performance is less crucial than flexibility.clause; columns not explicitly modified retain their previous values.There are two ways to modify a table using information contained in other tables in the database: using sub-selects, or specifying additional tables in the you should ensure that the join produces at most one output row for each row to be modified.Whenever you alter the value of a column referenced by the -- All the employees except the manager of -- department (WORKDEPT) 'E21' have been temporarily reassigned.-- Indicate this by changing their job (JOB) to NULL and their pay -- (SALARY, BONUS, COMM) values to zero in the EMPLOYEE table.I have highlighted the areas which differ compared with a normal cursor.
Previously when I've used cursors I've retrieved values into variables, then run an update query at each step based upon these values.The first syntactical form, called a searched update, updates the value of one or more columns for all rows of the table for which the WHERE clause evaluates to TRUE.The second syntactical form, called a positioned update, updates one or more columns on the current row of an open, updatable cursor.Because of this indeterminacy, referencing other tables only within sub-selects is safer, though often harder to read and slower than using a join.Attempt to insert a new stock item along with the quantity of stock.What I am trying to do is to select a target row - e.g. I'd hate to iterate through the entire table of millions of records.In arcpy, When you implement the Search Cursor or Update Cursor you have the option of using the where_clause parameter, which will allow you to select a specific row based on a field value (e.g. This help file will show you how to build an appropriate SQL query for selecting a specific row.There can be a situation where you have to use a cursor, even though the experts say not to use cursors or to avoid them as much as possible.But if you look closely, most of the time we use cursors to iterate through a row collection and update the same table.I have also attempted to use an update statement against cur PO, also unsuccessfully.I can make the code work by fetching to variables, but I'd like to know how to update the field directly. Address Type = '1801' update cur PO set Current POs = (select sum(Order Quantity) - sum(Receive Quantity) from #POs) drop table #POs fetch next from cur PO end close cur PO deallocate cur PO have aggregates in them that caused complications. Address Type = '1801') fetch next from cur PO end close cur PO deallocate cur PO I haven't tried this version yet, but it looks like it will have the same problem I described above.