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How to open a dynamic cursor in SQL Server?
Dynamic Cursor in SQL Server For UPDATE. In this example we will show you, How to declare, and open a dynamic cursor in SQL Server, and how to perform the Update operation within the dynamic cursor. For this, we are using the DECLARE CURSOR Statement, and within that, we will use the WHILE LOOP to loop over the cursor elements, and perform updates.
Can a cursor be used in a SELECT statement?
A cursor will only accept a select statement, so if the SQL really needs to be dynamic make the declare cursor part of the statement you are executing. For the below to work your server will have to be using global cursors.
How to update column fetched by a cursor in TSQL?
After doing a bit more googling, I found a partial solution. The update code is as follows: I still had to use FETCH INTO, however, to retrieve #t1.Product_ID and run the query that produces #POs, so I’d still like to know if it’s possible to use FETCH on it’s own.
Can a cursor be used to update a table?
A requirement has come in to denormalize the table for reporting purposes by adding a state description column. Now, you could use a cursor and loop through the table, updating each row, but cursors can be performance killers. You could also create multiple UPDATE statements, but that would be unwieldly.
Can a string variable be used to reuse a cursor?
Using a string variable to hold the query will prevent you from writing the query twice. Cursors are NOT designed to be re-used: you read them once, keep moving forward and as you’re doing so you’re discarding any previously scanned rows.
How to fetch the next record from dynamic cursor?
The below statement will fetch the next record from dynamic_employee_cursor into already declared variables. Then, we used the WHILE LOOP to loop over the cursor elements, and within the loop, FETCH_STATUS is used to check the status of the FETCH statement.
Can You Close and reopen the same cursor?
This is a feature, not a bug – cursors are intended to be very much memory/disk efficient. So the options are: 1) As Nicolas mentioned, close and re-open the same cursor.