I have this query in postgresql:
select *
from A s
join B m on (s.id=m.id)
where m.key=4 and s.ran=some_input_from_user
This gives me all the rows that I need to update.
I want to set A.value to be 90 for all these rows.
It doesn't look like a standart update query
if I do...
Update A set value=90 where.....
then I can't do the join.
any ideas how to do it?
This is the basic update syntax for PostgreSQL where you are updating based on a join to another table:
update A s
set
value = 90
from B m
where
s.id = m.id and
m.key = 4 and
s.ran = some_input_from_user
The trick is you never use the alias in the lvalue for the set commands. In other words, value = 90 is not s.value = 90. It seems minor, but I'm pretty sure it will prevent your query from working. The rationale is if you are updating table A (alias s) then any fields you are updating are, de-facto, from table A -- no need to alias them, and to allow aliases would almost imply you could update something other than A with this statement, which you cannot.
You can definitely use them in the rvalues, so this would certainly be okay (if it were your desire to update A based on B):
update A s
set
value = m.salary * s.commission
from B m
where
s.id = m.id and
(s.value is null or
s.value != m.salary * s.commission)
Here is the query:
update a set value = 90
where exists (
select 1 from b
where a.id = b.id and b.key=4
and a.ran=some_input_from_user);
The above query will eliminate the requirement of reading table a twice.
Also you can use this query:
update a set value = 90
where a.id in
(select b.id from b
where a.id = b.id and b.key = 4
and a.ran=some_input_from_user);
TRY THIS
UPDATE A
SET A.VALUE = 90
from A
join B m on (A.id=m.id)
where m.key=4 and s.ran=some_input_from_user
I have two tables. My first table A contains
Tran_Particular | Dr_Tran_Amt | BeneficiaryName | PRNNo
columns.
My second table B contains
BeneficiaryName | Dr_Tran_Amt | PRNNo
columns.
I want to update table A.PRNNo but When I am updating this on BeneficiaryName and Dr_Tran_Amt that time it updates only first value. But In table B there are two PRNNO's are exist and In table A also two different Tran_Particular are exist. I want to update unique PRNNO wrt Tran_Particular, BeneficiaryName and Dr_Tran_Amt.
Query.
update A
set a.PRNNo = b.PRNNo
from A a
inner join B b
on a.Dr_Tran_Amt= b.Amount
and a.BeneficiaryName = b.BeneficiaryName;
HoW to update this in SQL server.
The code below should get you only the first matching row (the lowest PRNNo value):
UPDATE A
SET a.PRNNo = b.PRNNo
FROM A a
INNER join B b
ON a.Dr_Tran_Amt = b.Amount
AND a.BeneficiaryName = b.BeneficiaryName
AND b.PRNNo = (SELECT MIN(c.PRNNo) FROM B c WHERE c.BeneficiaryName = B.BeneficiaryName AND c.Dr_Tran_Amt = b.Dr_Tran_Amt);
I have two two tables A and B in which both P columns are common and I need to use update command in table B only when both p values are same and C column from table A is given
What I am trying is:
update B
set P =100
where B.P=A.P
and A.C=60
But it's giving me error no such column A.P
You are updating table B and do not have reference to table A, so sqlite just does not know where to look for. Try this:
UPDATE B
SET P = 100
WHERE B.P IN (SELECT A.P
FROM A
WHERE A.C = 60)
You can do it like this
Update B set P = 100 WHERE B.P = (Select P from A WHERE C = 60)
This is quite easy and has been asked multiple times but I can't get it to work.
The SQL query I think should work is:
UPDATE table2
SET dst.a = dst.a + src.a,
dst.b = dst.b + src.b,
dst.c = dst.c + src.c,
dst.d = dst.d + src.d,
dst.e = dst.e + src.e
FROM table2 AS dst
INNER JOIN table1 AS src
ON dst.f = src.f
Using the update statement it is not possible because in sqlite joins in an update statement are not supported. See docs:
update statement
If you only wanted to update a single column to a static value, you could use a subquery in the update statement correctly. See this example: How do I make an UPDATE while joining tables on SQLite?
Now in your example, making an assumption that there is a unique key on "column f" - a workaround/solution I have come up with is using the replace statement:
replace into table2
(a, b, c, d, e, f, g)
select src.a, src.b, src.c, src.d, src.e, dest.f, dest.g
from table1 src
inner join table2 dest on src.f = dest.f
I also added an extra column to table2 "column g" to show how you'd "update" only some of the columns with this method.
One other thing to be cautious about is if you use "PRAGMA foreign_keys = ON;" it's possible to have issues with this as the row is effectively deleted and inserted.
I came up with an alternative technique using a TRIGGER and "reversing" the direction of the update, albeit at the cost of a dummy field in the source table.
In general terms, you have a Master table and an Updates table. You want to update some/all fields of records in Master from the corresponding fields in Updates linked by a key field Key.
Instead of UPDATE Master SET ... FROM Master INNER JOIN Updates ON Mater.Key = Updates.Key you do the following:
Add a dummy field TriggerField to the Updates table to act as the focus of the trigger.
Create a trigger on this field:
CREATE TRIGGER UpdateTrigger AFTER UPDATE OF TriggerField ON Updates
BEGIN
UPDATE Master SET
Field1 = OLD.Field1,
Field2 = OLD.Field2,
...
WHERE Master.Key = OLD.Key
END;
Launch the update process with the following:
UPDATE Updates SET TriggerField = NULL ;
Notes
The dummy field is merely an anchor for the trigger so that any other UPDATE Updates SET ... won't trigger the update into Master. If you only ever INSERT into Updates then you don't need it (and can remove the OF TriggerField clause when creating the trigger).
From some rough-and-ready timings, this seems to work about the same speed as REPLACE INTO but avoids the feels-slightly-wrong technique of removing and adding rows. It is also simpler if you are only updating a few fields in Master as you only list the ones you want to change.
It is orders of magnitude faster than the other alternative I've seen to UPDATE ... FROM which is:
UPDATE Master SET
Field1 = ( SELECT Field1 FROM Updates WHERE Mater.Key = Updates.Key ),
Field1 = ( SELECT Field1 FROM Updates WHERE Mater.Key = Updates.Key ),
...
;
Updating six fields over 1700 records was roughly 0.05s for Tony and my methods but 2.50s for the UPDATE ... ( SELECT... ) method.
AFTER UPDATE triggers on Master seem to fire as expected.
As Tony says, the solution is the replace into way but you can use the sqlite hidden field rowid to simulate full update with join like:
replace into table2
(rowid,a, b, c, d, e, f, g)
select dest.rowid,src.a, src.b, src.c, src.d, src.e, dest.f, dest.g
from table1 src
inner join table2 dest on src.f = dest.f
With this you recreate full rows if you don't have primary key for the replace or as standard method to do the updates with joins.
SQLITE does not support UPDATE with INNER JOIN nor do several other DB's. Inner Joins are nice and simple however it can be accomplished using just a UPDATE and a subquery select. By using a where clause and the 'IN' with a subquery and a additional subquery for the 'SET' the same result can always be accomplished. Below is how it's done.
UPDATE table2
SET a = a + (select a from table1 where table1.f = table2.f),
b = b + (select b from table1 where table1.f = table2.f),
c = c + (select c from table1 where table1.f = table2.f),
d = d + (select d from table1 where table1.f = table2.f),
e = e + (select e from table1 where table1.f = table2.f)
WHERE RowId IN (Select table2.RowId from table1 where table1.f = table2.f)
Use below query:
UPDATE table2
SET a = Z.a,
b = Z.b,
c = Z.c,
d = Z.d,
e = Z.e
FROM (SELECT dst.id,
dst.a + src.a AS a,
dst.b + src.b AS b,
dst.c + src.c AS c,
dst.d + src.d AS d,
dst.e + src.e AS e
FROM table2 AS dst
INNER JOIN table1 AS src ON dst.f = src.f
)Z
WHERE table2.id = z.id
Evening all,
Actually, it's night. About 11pm. My brain is shutting down and I need a bit of help so I can finish and go home :)
I have two tables - table a and table b.
I need to update a field in table a with the value from a field in table b when two other fields match. The tables don't have a unique id for each record :(
Basically, I want to do this:
update a
set importantField =
(select b.importantfield
from b
where a.matchfield = b.matchfield
and a.matchfield2 = b.matchfield2
)
where a.matchfield = b.matchfield
and a.matchfield2 = b.matchfield2
Or at least... I think that's what I want to do...
Can someone help me out, please?
You can do this via a join in the update:
Update a
Set a.importantField = b.importantField
From a Join b
On a.matchfield = b.matchfield
And a.matchfield2 = b.matchfield2
Use:
UPDATE TABLE_A
SET importantField = (SELECT b.importantfield
FROM TABLE_B b
WHERE b.matchfield = matchfield
AND b.matchfield2 = matchfield2)
SQL Server doesn't support table aliases on the table being updated, but the above is a correlated query - those fields without the table alias b attached will serve values from TABLE_A because it doesn't have an alias.
The only issue beyond that is if there are multiple b.importantfield values for records with the matching records to TABLE_A. Use:
UPDATE TABLE_A
SET importantField = (SELECT TOP 1
b.importantfield
FROM TABLE_B b
WHERE b.matchfield = matchfield
AND b.matchfield2 = matchfield2)
..but you should use an ORDER BY as well or you'll get any random b.importantfield value.