Thus, an update query runs faster if the column to be updated is not an index key column.
The index can always be created once the update completes. Executing the update in smaller batches The query can be further optimized by executing it in smaller batches. The code below updates the records in batches of 20000. Disabling Delete triggers Triggers with cursors can extremely slow down the performance of a delete query.
This command is used frequently in the removal of spam comments from Word Press blogs.
Word Press also includes a user-friendly method of mass-deleting or mass-editing comments via its handy “Mass Edit Mode” (WP Admin → Manage tab → Comments tab → Mass Edit Mode link).
There are 3 syntaxes for the UPDATE statement depending on whether you are performing a traditional update or updating one table with data from another table.
Updating very large tables can be a time taking task and sometimes it might take hours to finish.
Simply select any/all comments and click the “Delete Checked Comments” button.
The index update and Sort operation together take 64% of the execution cost. Removing index on the column to be updated The same query takes 14-18 seconds when there isn’t any index on col1.
INSERT INTO bought_in_control_panel(ID, PARENT_ID, BOUGHT_IN_FORM_TYPE_ID, PRIORITY, NAME, HEADING, DESCRIPTION, ICON, BOUGHT_IN_CONTROL_PANEL_FILE_ID) VALUES(109,1,28,100,'Tooling','Tooling','Enter your Machine Tools here','tooling.png',null); UPDATE ON ID bought_in_control_panel(ID, PARENT_ID, BOUGHT_IN_FORM_TYPE_ID, PRIORITY, NAME, HEADING, DESCRIPTION, ICON, BOUGHT_IN_CONTROL_PANEL_FILE_ID) VALUES( (109,1,28,100,'Tooling','Tooling','Enter your Machine Tools here','tooling.png',null), (1,0,1,200,'Bought In','Bought In','','boughtin.png',null) ); values, and update the matches with the new data.
Note: I am really looking to avoid manually mapping all the column names.
verify the data ends up as you expect for a couple records.
In other words I want to do something like this: If you are planning on running this on a PROD DB, it is best to create a snapshot or mirror of it first and test it out.