Résultats de recherche
UPDATE table1 t1 SET (name, desc) = (SELECT t2.name, t2.desc FROM table2 t2 WHERE t1.id = t2.id) WHERE EXISTS ( SELECT 1 FROM table2 t2 WHERE t1.id = t2.id ) Assuming the join results in a key-preserved view, you could also
- Setup
- Subquery Method
- Inline View Method
- Merge Statement Method
The DEST_TAB table contains 10,000 rows. The SOURCE_TAB table contains 5,000 rows, each of which has a matching key value with a row from the DEST_TAB table, but different data in the CODE and DESCRIPTIONcolumns. At this point we can see none of the values in the DESCRIPTION column of the DEST_TABtable contain the word "Updated". The aim is to upda...
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_TABtable. Without this, the unmatched rows will have their values set to NULL. The execution plan for the current data v...
The second option is to join the two tables as an inline view and base the update on that. The execution plan for the current data volume is shown below. If the workload is sufficiently large and the server can cope with the extra workload, the PARALLELhint can be used to make this run in parallel. The number of rows updated can be altered by addin...
The third option is to use the MERGE statement, omitting the WHEN NOT MATCHEDclause as it is not needed. The execution plan for the current data volume is shown below. If the workload is sufficiently large and the server can cope with the extra workload, the PARALLELhint can be used to make this run in parallel. Remember, you can use queries as the...
27 juin 2011 · La méthode classique pour réaliser cette modification est d'utiliser un update et une sous-requête corrélée. Sélectionnez update bigemp e set e.sal = e.sal + ( select a.Montant from augmentation a where a.empno = e.empno ) where e.empno in ( select a.empno from augmentation a )
26 déc. 2023 · Oracle Update Table From Another Table 1. Use the MERGE statement to update rows in a table based on the values in another table. 2. Specify the source and target tables, the join condition, and the update columns. 3. Use the WHEN MATCHED and WHEN NOT MATCHED clauses to control how rows are updated.
The Oracle UPDATE statement is used to update existing records in a table in an Oracle database. There are 2 syntaxes for an update query in Oracle depending on whether you are performing a traditional update or updating one table with data from another table.
6 avr. 2024 · The Oracle SQL UPDATE FROM SELECT statement is a versatile command that can simplify data synchronization tasks and apply complex update logic. By understanding its syntax and best practices, you can write efficient and maintainable SQL code that keeps your data consistent and up-to-date.
15 mai 2020 · If you've ever found updating tables using data from another table in Oracle to be a challenging and slow process, you're not alone. In this article, we delve into the powerful MERGE statement and how it can revolutionize your database operations.
