Firstly, let us view the syntax for Oracle update with Join clause to update a single table typed as follows:. The other type of oracle syntax for update with join while updating a single table with data from the other table is as follows:. The Update with Join query works in Oracle by the following steps where we have supposed to have two tables Orders and OrderInfo like shown below which will be simple to elaborate also:.
Now, we will perform the update query with JOIN clause on table orderInfo based on the Orders table column values so that the resultant table provides an output of join using the query command as:.
OrderNum SET orderinfo. In the same way, we can use the left join clause with the update statement so that the query results or updates the table columns on the left side of the LEFT JOIN clause according to the matched values otherwise with NULL. To update single table column: We will execute a simple update query statement in Oracle written below and also view the table named Orders first to see the column values present as follows:. Let us query the update statement command in oracle where multiple columns update can be performed with one update command query as follows:.
Here, to update multiple table columns we have separated the value pairs with commas, therefore, the output will be as shown above where mentioned column value pairs are updated. We will execute the update statement in Oracle that will update the columns values from other table as follows:.
In this article, we have learned about the Oracle Update with Join query which is responsible for execution of the cross-table update. But rather, Wien in German or Vienna in English:. We can also update the invoice table based on a customer. For example, suppose we need to give a special discount on the total invoice for Austrian customers who spent more than 20 dollars on Rock and Metal genre 1 and 3. The subset is easily extracted with the following query:.
We can apply it updating the total invoice table based on the above query using the below CTE:. How does this work in Oracle?
We must do some shortcuts in order to do something similar. We can make use of a subquery and an IN filter. We will transform the UPDATE statement using the above query as a subquery, but we will extract the primary key Invoiceid in order to do the update:. That was quite easy, but let's suppose that we need to an UPDATE based on another big table and use the value in the other table. But this time it is a select statement with the primary key and the total that we'd like to update.
I've put this result as the table to update. It is a workaround, but it works! Only thing you have to be careful about is ensuring that the results are unique and you are not trying to update more rows than the ones you need.
This is why I always do a select before to check how many rows should be updated. This should be written like this:. As you can see, it is more readable than the previous solution.
NEW It depends if the inline view is considered updateable by Oracle To be updatable for the second statement depends on some rules listed here. Tony Andrews Tony Andrews k 20 20 gold badges silver badges bronze badges. I did the second example but had to add aliases to the column names in the select and then reference them by their names in the SET but it worked, thanks — Gustavo Rubio.
The second example has the benefit of allowing you to test the SQL before actually performing the update. The second example worked for me. I like that one because it looks clean and readable. Don't know what the pros and cons are between the two when it comes to performance. But, I wasn't worried about that for now 'cuz I used this for a one off script to correct bad data. Explanation on key-preserved requirement for updatable joins: asktom. Got this - "ORA cannot modify a column which maps to a non key-preserved table", and then stackoverflow.
Show 7 more comments. Quassnoi Quassnoi k 88 88 gold badges silver badges bronze badges. Works perfectly but Oracle required me to say merge into table 1 t and so forth. Late to the party, but this is still a good thread.
I need to know, tho' Master table, "table1". Table2, aliased as t2, but in the ON, the references are External Table1 - not t1 - is this a reference to the outer table or a type? Not t2? Je suis confused. Fan of better aliases Just a point here, if your key trg. Marc In the ON , trg is the alias for the master table, table1 "outer" table by your logic , and src references the USING group "inner table" by your logic.
But yeah, probably could've been referenced better, but I was able to follow it. This can work in some cases, but the view has to be "key-preserved" every joined table has to be equality-joined on its primary key or otherwise unique fieldset. This makes sure every record in the target table contributes to at most one record in the resulting rowset, and, hence, every record in the target table is updated at most once.
Show 3 more comments. Roland Roland 6, 11 11 gold badges 55 55 silver badges bronze badges. This version is arguably cleaner, but it is not trigger friendly because there is no way I am aware of to avoid triggering update triggers for unchanged rows using this syntax.
I am assuming that the triggers are needed for the changed rows. Do not use some of the answers above. Also, ensure that there are primary keys on all the tables you are joining. Morten Anderson Morten Anderson 2, 14 14 silver badges 19 19 bronze badges.
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