Sql updating table from temp table helpdating
Furthermore, the scope of any particular temporary table is the session in which it is created; meaning it is only visible to the current user.Multiple users could create a temp table named #Table X and any queries run simultaneously would not affect one another - they would remain autonomous transactions and the tables would remain autonomous objects.
To create a gap, delete employee record from the #Employee table with id = 2 by the following script: RESULT: Now let us run the example 1’s approach 1 and 2 script on #Employee table which is having gap in the Id column value (i.e. From the above result it is clear that the example 1’s approach 1 and 2 script will not work in the scenarios where we have gap in the looping tables column values.With the addition of temporary tables to hold the intermediate results, this query runs in less than three seconds, a 6 performance increase.Again, it is not easy to quantify the reason for this speed increase, since the DBA views do not map directly to Oracle tables, but it is clear that temporary table show promise for improving the execution speed of certain types of Oracle SQL queries.Consider a help desk application that allows support staff to create support tickets, where each ticket in the system exists as a record in the Tickets table. To ease data entry, let's say that administrative users can create "ticket templates," which pre-define the values for a number of ticket data points that are stored in a table named Ticket Templates. Applying a template to an existing ticket would require that the existing record in the Tickets table have its non-set data points assigned to the corresponding default values of the selected template.