I'm attempting to perform a LEFT JOIN on a table to consolidate some data, but I'd like to rename one of the fields I'm joining.
LEFT JOIN (SELECT email FROM user_email) AS foo ON (user_id = users.user_id)
I can select that data using foo.email, but I'd like to rename this field in the join so I can reference foo.user_email. What's the correct way to perform this?
LEFT JOIN (SELECT email as user_email FROM user_email) AS foo ON (user_id = users.user_id)
Related
I would like to do a single left join from table a onto table b on transaction_id
select a.*, b.*
from tablea a
left join tableb b on b.transaction_id = a.transaction_id
However, there are cases where transaction id on either table is missing, in which case I would like to fall back onto joining on a.user_id = b.user_id. If user_id is also missing then fine, I still want to keep all records from a.
Is there a way I can tell postgres to try joining on one field and if it's missing on either table to then try joining on another field?
Is there a way to do this?
Add a 2nd join to tableb with the condition that the 1st join did not match:
select a.*,
coalesce(b1.col1, b2.col1), coalesce(b1.col2, b2.col2), .....
from tablea a
left join tableb b1 on b1.transaction_id = a.transaction_id
left join tableb b2 on b2.user_id = a.user_id and b1.transaction_id is null
I have a many to many relation with three columns, (owner_id,property_id,ownership_perc) and for this table applies (many owners have many properties).
So I would like to find all the owner_id who has many properties (property_id) and connect them with other three tables (Table 1,3,4) in order to get further information for the requested result.
All the tables that I'm using are
Table 1: owner (id_owner,name)
Table 2: owner_property (owner_id,property_id,ownership_perc)
Table 3: property(id_property,building_id)
Table 4: building(id_building,address,region)
So, when I'm trying it like this, the query runs but it returns empty.
SELECT address,region,name
FROM owner_property
JOIN property ON owner_property.property_id = property.id_property
JOIN owner ON owner.id_owner = owner_property.owner_id
JOIN building ON property.building_id=building.id_building
GROUP BY owner_id,address,region,name
HAVING count(owner_id) > 1
ORDER BY owner_id;
Only when I'm trying the code below, it returns the owner_id who has many properties (see image below) but without joining it with the other three tables:
SELECT a.*
FROM owner_property a
JOIN (SELECT owner_id, COUNT(owner_id)
FROM owner_property
GROUP BY owner_id
HAVING COUNT(owner_id)>1) b
ON a.owner_id = b.owner_id
ORDER BY a.owner_id,property_id ASC;
So, is there any suggestion on what I'm doing wrong when I'm joining the tables? Thank you!
This query:
SELECT owner_id
FROM owner_property
GROUP BY owner_id
HAVING COUNT(property_id) > 1
returns all the owner_ids with more than 1 property_ids.
If there is a case of duplicates in the combination of owner_id and property_id then instead of COUNT(property_id) use COUNT(DISTINCT property_id) in the HAVING clause.
So join it to the other tables:
SELECT b.address, b.region, o.name
FROM (
SELECT owner_id
FROM owner_property
GROUP BY owner_id
HAVING COUNT(property_id) > 1
) t
INNER JOIN owner_property op ON op.owner_id = t.owner_id
INNER JOIN property p ON op.property_id = p.id_property
INNER JOIN owner o ON o.id_owner = op.owner_id
INNER JOIN building b ON p.building_id = b.id_building
ORDER BY op.owner_id, op.property_id ASC;
Always qualify the column names with the table name/alias.
You can try to use a correlated subquery that counts the ownerships with EXISTS in the WHERE clause.
SELECT b1.address,
b1.region,
o1.name
FROM owner_property op1
INNER JOIN owner o1
ON o1.id_owner = op1.owner_id
INNER JOIN property p1
ON p1.id_property = op1.property_id
INNER JOIN building b1
ON b1.id_building = p1.building_id
WHERE EXISTS (SELECT ''
FROM owner_property op2
WHERE op2.owner_id = op1.owner_id
HAVING count(*) > 1);
I would like to have table A's cateogry column join in the table B. How to write the join in same table?
Here is the sql script for table A
select code_id, code_desc category
FROM t_setup_code
WHERE code_id IN (select code_1 from t_setup_code WHERE code_desc LIKE 'Ag%');
Here is the sql script for table B
SELECT a.plot_sub_usage, b.code_id, b.code_1, b.code_desc, COUNT(*)
FROM dc_plot a, t_setup_code b
WHERE a.plot_sub_usage = b.code_id
AND b.code_id LIKE 'LUC-AG%'
GROUP BY a.plot_sub_usage, b.code_desc, b.code_id, b.code_1
ORDER BY a.plot_sub_usage;
Here is the results for both sql scripts
Result should look like this:
Try this
SELECT a.plot_sub_usage, b.code_desc, c.code_desc, COUNT(*)
FROM dc_plot a
inner join t_setup_code b on a.plot_sub_usage = b.code_id
inner join t_setup_code c on c.code_id = b.code_1
WHERE b.code_id LIKE 'LUC-AG%'
AND c.code_desc like 'Ag%'
GROUP BY a.plot_sub_usage, b.code_desc, c.code_desc
ORDER BY a.plot_sub_usage;
I have a big query, but it all boils down to this:
SELECT * FROM user
LEFT JOIN tableA ON tableA.user_id = user.id
JOIN tableB ON tableB.a_id = tableA.id
Now, I get too few results. If the combination of user with (tableA x tableB) does not exist, I still want the user. So with syntax error, what I want is something like this:
SELECT * FROM user
LEFT JOIN (tableA ON tableA.user_id = user.id
JOIN tableB ON tableB.a_id = tableA.id)
is that possible, perhaps without RIGHT JOINS?
Of course, I don't want to change the second JOIN to LEFT JOIN, because that would give too many results.
You can try this:
SELECT * FROM user
LEFT JOIN (SELECT * FROM tableA
JOIN tableB ON tableB.a_id = tableA.id) t
ON t.user_id = user.id
You will need to select distinct columns in subquery here if any exists.
I have a stored procedure which is running quite slow. Therefore I want to extract some of the query in a separate view.
My code looks something like this:
DECLARE #tmpTable TABLE(..)
INSERT INTO #tmpTable (..) *query* (returns 3000 rows)
Select ... from table1
inner join table2
inner join table3
inner join #tmpTable
...
I then extract (copy-paste) the *query* and put it in a view - i.e. vView.
Doing this will then give me a different result:
Select ... from table1
inner join table2
inner join table3
inner join vView
...
Why? I can see that the vView and the #tmpTable both returns 3000 rows, so they should match (also did a except query to check).
Any comments would be much appriciated as I feel quite stuck with this..
EDITED:
This is the full query for getting the result (using #tmpTable or vView gives me different results, although the appear the same):
select dep.sid as depsid, dep.[name], COUNT(b.sid) as possiblelogins, count(ls.clientsid) as logins
from department dep
inner join relationship r on dep.sid=r.primarysid and r.relationshiptypeid=27 and r.validto is null
inner join [user] u on r.secondarysid=u.sid
inner join relationship r2 on u.sid=r2.secondarysid and r2.validto is null and r2.relationshiptypeid in (1,37)
inner join client c on r2.primarysid=c.sid
inner join ***#tmpTable or vView*** b on b.sid = c.sid
left outer join (select distinct clientsid from logonstatistics) as ls on b.sid=ls.clientsid
GROUP BY dep.sid, dep.[name],dep.isdepartment
HAVING dep.isdepartment=1
You maybe don't need the view/table if you change to this.
It joins on to client c and appears to be there only to JOIN onto logonstatistics
--remove inner join ***#tmpTable or vView*** b on b.sid = c.sid
--change JOIN
left outer join (select distinct clientsid from logonstatistics) as ls on c.sid=ls.clientsid
And change COUNT(b.sid) to COUNT(c.sid) in the SELECT clause
Otherwise, if you get different results you have two options I can see:
Table and view have different data. Have you run a line by line comparsion?
One has NULL, one has a value (especially for the sid column which will affect the JOIN)
Finally, when you says "different results" do you mean you get x2 or x3 rows? A different COUNT? What?