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If you want to update specific rows (ie where the IDs match) you probably want to do a coordinated subquery. However, since you are using Oracle, it might be easier to create a materialized view for your query table and let Oracle's transaction mechanism handle the details.
6 gru 2017 · Learn about several methods to update data using subqueries in UPDATE statements to make them more effective and easier to maintain in Oracle SQL.
Subquery Method. The first option is to do an update of the DEST_TAB table using a subquery to pull the correct data from the SOURCE_TAB table. Notice the EXISTS predicate to exclude rows from the DEST_TAB table with no matching row in the SOURCE_TAB table.
30 maj 2011 · UPDATE table_a a SET field_2 = ( SELECT field_2 FROM table_b b WHERE b.id = a.id ) ; Now, each time the above is executed, it will do it across all rows in the table.
4 sie 2024 · Ever found yourself needing to update a bunch of rows in your database, but the condition for the update depends on data from another table? That’s where UPDATE with a subquery comes in handy. Let’s break it down.
A subquery is a SELECTstatement nested inside another statement such as SELECT, INSERT, UPDATE, or DELETE. Typically, you can use a subquery anywhere that you use an expression. Consider this following subquery example that uses the productstable from the sample database.
You may use subqueries in place of tables in this way as well in INSERT, UPDATE, and DELETE statements. Subqueries so used can employ correlation variables, both defined within the subquery itself and those defined in query blocks containing the subquery.
