Update Statement Help Please

Question

I'm coming from the MS SQL world LOL
and Im trying to write an update statement but in Oracle there is no INNER JOIN.
Can you give me some advice on how to do this please?
UPDATE employee
SET employee.name = tmpuser.name
FROM employee
INNER JOIN tmpuser
on tmpuser.emp_id = employtee.emp_id
Thank you for you help.
P

Answer 1

Hi,
AJR wrote:
Frank,
But when we are using the where condition it should update records with the matching ids. right?What your query should do is entirely up to you; I can't answer any questions about that, only you can.
I have faced this issue earlier.
WHERE       tmpuser.emp_id = employee.emp_idCan you explain?Not out of context. Post a complete statement.
If this isn't directly related to user9170886's problem, then it's better to start your own thread.
I can say a few things about UPDATE statements in general:
The WHERE clause governs which rows will be UPDATEd. If there is no WHERE clause, all rows in the table will be UPDATEd.
So
UPDATE     employee
SET     employee_name = ( <subquery> )
;UPDATEs every row in employee, because the UPDATE statement does not have a WHERE clause. Nothing in the sub-query can change that.
A sub-query can reference values from its immediate parent, but a parent can't reference values from a sub-query (other than the values actually returned by the sub-query, of course).
So
UPDATE     employee
SET     employee_name = ( <subquery> )
WHERE     tmpuser.emp_id     = employee.emp_id
;causes an error, because there is no table called tmpuser in the main UPDATE statement. Nothing in the sub-query can change that.