I have 2 tables A and B with the following columns
Table A - id,bId,aName,aVal
Table B - id,bName
where A.bId is the same as B.id. I want a result set from a query to get
A.id, A.aName, B.bName where A.bId=B.id OR
A.id, A.aName, "" when A.bId=0.
In both cases, only those records should be considered where A.aVal LIKE "aVal"
Can someone please help me with the query? I can use left join but how do I get the blank string if bId=0 and B.bName otherwise?
Thanks
SELECT a.id, a.aname, COALESCE(b.bname, '')
FROM a
LEFT JOIN
b
ON b.id = NULLIF(a.bld, 0)
WHERE a.aval LIKE 'aval'
Related
I have the following Hive query:
select *
from A
left outer join B
on A.ID = B.ID
where B.ID IS NULL
The result produces duplicate data but I need only non-duplicate records.
After some research, I tried the below query:
select *
from (
select *
from A
left outer join on B
where A.ID = B.ID AND B.ID IS NULL ) join_result
group by jojn_result.ID
It's showing an ambiguous column reference ID error.
I do not have the columns name of table A.
Please help me to identify the solution to this .
Thank you .
Hmmm . . . How about select:
Select A.*
from A left outer join
B
on A.ID = B.ID
where B.ID IS NULL;
I removed the B columns because they are not needed.
One of your join columns may have NULL values. Whenever there is NULL in any of the join key values, it will skip that column. Try replacing the NULL with some default value while joining using NVL or COALESCE. I was looking for same answer and saw your post here. But there was no solution. But since i found the solution I just wanted to post here so that someone can benefit.
select *
from A
left outer join B
on coalesce(A.ID,000) = coalesce(B.ID,000)
where B.ID IS NULL
Can anyone help me figure out the correct WHERE clause for the following scenario:
select A.name
from tableA A, tableB B
where A.id = B.id
and
(
B.field = 5
OR
B.hasNoRowForJoinedID
)
I feel like I'm missing something really obvious here in how to accomplish this, but I can't for the life of me put my finger on it.
You are using an outdated SQL Syntax. To perform the LEFT OUTER JOIN based your your request above, you can do the following:
SELECT A.name
FROM A
LEFT OUTER JOIN B ON A.id = B.id
WHERE (B.field = 5 OR B.field IS NULL)
Use proper join syntax and not the outdated ones:
select A.name
from tableA A
left join tableB B on A.id = B.id and B.field = 5
I am working on a project, and need to join results from 2 tables into one set.
The tables are ordered as such:
gameData: [Id,TeamID, data..........]
players: [Id (same as above), name, data.....]
I need to do something like:
SELECT * FROM gameData and SELECT data FROM players WHERE gameData.Id = players.Id
And here is what I have thusfar.
SELECT * FROM gameData AS A LEFT OUTER JOIN players AS B on A.playerID = B.Id;
And have it return all of the values from A, and only the data from B.
I know that the syntax is not correct, I have little experience working with SQL Joins, any advice would be greatly appreciated!
Edit: Trying both answers now. Thanks!
Edit2: Can I do something like: "Select a.* from tableA as a"
I love you guys, working as intended now!
Thanks!
The query I ended up using was:
Select a.*, b.height, b.weight from gameData as a LEFT OUTER JOIN players b on a.playerID = b.Id;
You could enumerate the fields that you select and alias the tables, like:
select a.Id, a.TeamId, a.data, b.data
from tableA a
join tableB b on a.Id = b.Id
Select a.Id, a.TeamID, a.data, b.data
FROM gameData as a
LEFT OUTER JOIN
players b On a.ID = b.ID
I used the query below to extract the data fro the table but it does not working.
SELECT A.ID, AVG(ISNULL(score,0)) AS sc FROM A
LEFT OUTER JOIN B ON A.ID = B.ID
WHERE A.aClass = '1st'
I wanted it to return all the data from Table A with its corresponding average score and return 0 if there is no score yet. Can anyone help me figure out the problem.
Try this
SELECT A.ID, AVG(ISNULL(B.score,0)) AS sc
FROM A
LEFT OUTER JOIN B ON A.ID = B.ID
WHERE A.aClass = '1st'
GROUP BY A.ID
This is evidently correct syntax in SQL Server:
SELECT a.id, b.name
FROM Table1 a, Table2 b
WHERE a.id = b.fk1
So is this:
SELECT a.id, c.status
FROM Table1 a
JOIN Table3 c ON a.id = c.fk2
But this apparently isn't:
SELECT a.id, b.name, c.status
FROM Table1 a, Table2 b
JOIN Table3 c ON a.id = c.fk2
WHERE a.id = b.fk1
I would NOT normally want to construct a query in the third case's style (and really not the first case's either), but it would probably be the path of least resistence in editing some code that's already been written at my company. Somebody used the first form with five different tables, and I really need to work in a sixth table through a JOIN statement, without taking chances of messing up what they already have. Even though I could re-write their stuff outright if I need to, I would really like to know how to do something like in the third case.
Running the code exactly as-is in the examples, the third case gives me this error message:
The multi-part identifier "a.id" could not be bound.
What is syntactically breaking the third case? What simple fix could be applied? Thanks!
I, likewise, would not recommend doing this. But, you can just change the , to a cross join:
SELECT a.id, b.name, c.status
FROM Table1 a cross join Table2 b
JOIN Table3 c ON a.id = c.fk2
WHERE a.id = b.fk1
This code:
SELECT a.id, b.name, c.status
FROM Table1 a, Table2 b
JOIN Table3 c ON a.id = c.fk2
WHERE a.id = b.fk1
is doing a cross join on a and the result of an inner join on b and c. c cannot access any of the fields in a because the join is being performed on b. what you should do is change your query to:
SELECT a.id, b.name, c.status
FROM Table1 a
inner join Table2 b on a.id = b.fk1
inner JOIN Table3 c ON a.id = c.fk2