We are going to update column DESCRIPTION and PICTURE in table Categories_Test by using data in table Categories, based on data in the common column CATEGORY_ID. Update data in a column in table A based on a common column in table B. Update data in two columns in table A based on a common column in table B. Conditionally update data in table A based on a common column in table B. No portion may be reproduced without my written permission.
The update query below shows that the PICTURE column is updated by looking up the same ID value in CATEGORY_ID column in table Categories_Test and Categories. If you need to update multiple columns simultaneously, use comma to separate each column after the SET keyword. Here we only want to update PICTURE column in Categories_Test table where the data in Category_Name column is Seafood in table Categories. Software and hardware names mentioned on this site are registered trademarks of their respective companies.
We can create a trigger to update the 'product_price_history' table when the price of the product is updated in the 'product' table.
1) Create the 'product' table and 'product_price_history' table Once the above update query is executed, the trigger fires and updates the 'product_price_history' table.
1) Row level trigger - An event is triggered for each row upated, inserted or deleted.
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What I love about writing SQL Tuning articles is that I very rarely end up publishing the findings I set out to achieve. We have a table containing years worth of data, most of which is static; we are updating selected rows that were recently inserted and are still volatile. For the purposes of the test, we will assume that the target table of the update is arbitrarily large, and we want to avoid things like full-scans and index rebuilds.
With this one, I set out to demonstrate the advantages of PARALLEL DML, didn't find what I thought I would, and ended up testing 8 different techniques to find out how they differed. The methods covered include both PL/SQL and SQL approaches.
Using an oracle DB, 11g r2, I need to write a pl/sql which updates one column in table A where the PK exists in table B, with commits ever ~50,00 rows.
3200000 rows are involved in the update, and table A has ~70 million rows total.
I spend an inordinate proportion of design time of an ETL system worrying about the relative proportion of rows inserted vs updated.