I am trying to update my table 1 with some field value from table 2 based on a condition. But am unable to get the proper query. Here's the condition:
I have a table 1 with date field which should be updated from table 2 date field. The condition is that the id of table 1 should be equal to id of table 2 (Table 2 has id of table 1 as FK). Another condition should be there is a varchar field in table 2 which should have specific value, say "Test". Wherever the value of field in table 2 is "Test" I want to update the date of with that record in table 1 date field. But there is another catch. It may be possible that more than 1 records for same id in table 2 can have value as "Test"
I was trying the query as:
UPDATE A
SET A.Date = Max(B.[Date])
FROM Table1 A
INNER JOIN Table2 B ON A.ID = B.FK_ID
WHERE (B.Changed LIKE 'Test')
AND A.Date IS NULL
But this is not working as sql does not allow Max in update when there is no group by. Please help. A bit urgent.
You need to create another inner join where the ID's of Table1 are coupled with the maximum dates of Table2 like so:
UPDATE Table1
SET Date = BDate.MaxDate
FROM Table1 A
INNER JOIN Table2 B ON A.ID = b.FK_ID
INNER JOIN (
SELECT A.ID, [MaxDate] = MAX(B.Date)
FROM Table1 A
INNER JOIN Table2 B ON A.ID = b.FK_ID
GROUP BY A.ID
) BDate ON BDate.ID = A.ID
WHERE B.Changed LIKE 'Test'
A.Date IS NULL
You could always use subqueries:
UPDATE Table1 a SET
[Date] = (SELECT MAX([Date]) FROM Table2 b WHERE a.ID = b.FK_ID AND b.Changed LIKE 'Test')
WHERE [Date] IS NULL
Related
I have two tables like this :
TableA
Id | ProjectId | JobId
TableB
Id | Title
I want to write a query returning TableB Ids that are not in TableA with ProjectId = 2.
I've written a query like
Select B.Id
From TableB B
Right Join TableA A On B.Id = A.JobId
Where B.JobId Is Null And A.ProjectId = 2
But it returns zero output.
Thanks
I would use EXISTS here:
SELECT b.Id
FROM TableB b
WHERE NOT EXISTS (SELECT 1 FROM TableA a WHERE a.JobId = b.Id AND a.ProjectId = 2);
Reading in English terms, the above says to select every Id in TableB such that we cannot find an equal Id in TableA whose ProjectId is also 2.
Query edited
I have a database in PostgreSQL and I'm having some problems updating some values, let me explain.
I have three tables.
Table A:
id | itemID | Value
Table B:
Name | Value
Table C:
itemID | Name
I need to update the value field on table A with the value from table B where the itemId from the tables A and C are equal.
I don't really know how to explain, please ask me anything so I can explain it better
You need a join in the UPDATE statement:
update tablea
set "Value" = b."Value"
from tableb b inner join tablec c
on c.name = b.name
where c."itemID" = tablea."itemID";
See the demo.
You can use Update statement with a Common Table Expression, and bring the results directly by adding returning clause at the end.
with t0 as
(
select c.itemID , b.value
from tableC c
left join tableB b on b.name = c.name
)
update tableA a
set value = t0.value
from t0
where a.itemID = t0.itemID
returning a.*;
Demo
I'm struggling getting this query to produce the results I want.
I have:
table1, columns=empid, alt_id
table2, columns=empid, alt_id
I want to get the empid, and alt_id from table 1 where the alt_id does not match the alt_id in table2. They will both have alt_id numbers I just want to get the ones that do not match.
Any ideas?
SELECT * FROM table1
INNER JOIN table2 ON table2.empid = table1.empid AND table2.alt_id <> table1.alt_id
What does that really mean though? Normally when this is asked, it is of the form "I want all rows from A that have no row matching in B and all in B that have no match in A"
Which looks like this:
SELECT * FROM
A
FULL OUTER JOIN
B
ON
a.id = b.id
You'll see a null for any row data where there isn't a matching row on the other side:
A.id
1
2
B.id
1
3
Result of full outer join:
A.id B.id
1 1
2 null
null 3
You, however have asked for A-B join where the IDs aren't equal, which would be the more useless query of:
SELECT * FROM
A
INNER JOIN
B
ON
a.id != b.id
And it would look like:
A.id B.id
1 3
2 1
2 3
You seem to want not exists:
select t1.*
from table1 t1
where not exists (select 1 from table2 t2 where t2.alt_id = t1.alt_id);
It is unclear whether or not you also want to join on empid, so you might really want:
select t1.*
from table1 t1
where not exists (select 1 from table2 t2 where t2.alt_id = t1.alt_id and t2.empid = t1.empid);
A left join will find all records in Table A that do not match those in Table B. Then use a Where filter to find the Nulls from Table B. That will give you all those in Table A that do not have a matching ID in Table B.
Select A.*
from Table A
Left Join
Table B
on a.altid = b.altid
where b.altid is null;
select *
from [Login] L inner join Employee E
on l.EmployeeID = e.EmployeeID
where l.EmployeeID not in (select EmployeeID from Employee)
Table A:
id Name
1 a
2 b
3 c
4 d
5 e
Table B:
id Name
3 c
4 d
5 e
Here, id is the primary key connected to Table B.
I need output like this:-
id
1
2
That means, which ids in Table A are not present in Table B
Use EXCEPT operator:
select id from tableA
except
select id from tableB
You can use a left join, which will preserve all records on the left side and associate them with null if no matching record is available on the right side.
This way you can then filter on the right side columns to be null to get the desired outcome
select t1.id
from tableA t1
left join
tableB t2
on t1.id = t2.id
where t2.id is null
Use NOT EXISTS in WHERE clause
SELECT id FROM TableA A
WHERE NOT EXISTS(SELECT 1 FROM TableB B WHERE A.id = B.Id )
Using Not in statement.
Try this:-
Select id from TableA
where id not in (Select id from TableB);
You can use minus:
select * from tableA
minus
select * from tableB
I am using Oracle and I am trying to update a table(A) with data from another table(B). Not every field in B has a value so I have a number of NULL entries. When I run the update it says 6000 rows updated. Now there are 6000 rows in table B, however for this query only 14 have data in. When I select count(*) from both tables for this value they both return 14 rows each. Why is it reporting that 6000 rows have been updated?
UPDATE
table1 A
SET
phone_work = (
SELECT B.phone_work
FROM table2 B
WHERE B.id = A.applicant_id)
WHERE EXISTS (
SELECT 1
FROM table2 B
WHERE B.id = A.applicant_id);
I have also tried the following and I get the same result:
UPDATE
table1 A
SET
phone_work = (
SELECT B.phone_work
FROM table2 B
WHERE B.id = A.applicant_id
AND B.phone_work is not null
)
WHERE EXISTS (
SELECT 1
FROM table2 B
WHERE B.id = A.applicant_id);
Why is it reporting the update of 6000 rows? When I change the fields but use the same syntax it reports updating of the exact number of rows I expect e.g. a count of table B has 86 entries in the NAME field and it reports 86 rows updated. It seems that with the phone_work field I am getting every null value being counted as an update.
Perhaps you want to check for the non-NULL value in the exists:
UPDATE table1 A
SET phone_work = (SELECT B.phone_work
FROM table2 B
WHERE B.id = A.applicant_id
)
WHERE EXISTS (SELECT 1
FROM table2 B
WHERE B.id = A.applicant_id AND B.phone_work IS NOT NULL
);
Try this:
UPDATE
(
SELECT A.phone_work Aphone, B.phone_work Bphone
FROM table2 B, table1 A
WHERE B.id = A.applicant_id AND B.phone_work IS NOT NULL
)
SET
Aphone = Bphone;
Source: Oracle SQL: Update a table with data from another table