These are the tables that i have(I got this):
table building: b_id(key relation with table build-works b_id):1 2 3
field1: buildingA, buildingB,
buildingC
table build-works: b_id:1 1 2 3 3 3
w_id: 1 2 1 1 2 3
table works: w_id(key relation with table build-works w_id): 1 2 3 4
field1: electricity, sanitary, shell,
roofing
Now I want to know the works per building?
How can i do this with sql, and can you give my the example also with zend_db?
Thanks
using left joins since its in the title
SELECT *
FROM building b
LEFT JOIN buildworks bw
ON b.b_id = bw.b_od
LEFT JOIN works w
ON bw.w_id = w.w_id
Assuming b_id is the primary key for building, (b_id, w_id) is key for build_works, and w_id is key for works you can do it as follows:
Project_building.field1,works.field1(building JOIN build_works JOIN works)
Note that you have to rename field1 of works to something else when doing JOIN.
Also note that this might not be the most efficient way to do it.
Related
I'm trying to join two tables in postgresql with the following structure, which is the relation between some areas and some points surrounding it
Table 1 "d_hid_t"
id_rank | dem_hid_m3s
1 3.6
2 3.45
3 3.40
4 2.35
5 2.33
Table 2 "disph"
id_rank | disph_m3s
1 0.058
1 1.36
1 1833.4
2 0.017
2 208.69
3 0.39
3 40.79
... ...
I'm expecting to get the join output based on the maximum value found for the unique ID of table 1, without repeating the other related values, for example
Table 3 "output"
id_rank | disph_m3s
1 1833.4
2 208.69
3 40.69
... ...
So far I followed some instruction on this stack overflow post Select first record in a One-to-Many relation using left join but with no success. I keep getting the error "aggregate functions are not allowed in JOIN conditions".
Right now my code looks like this:
SELECT a.id_rank, a.dem_hid_m3s, a.geom, b.id_disp, b.dist_km, b.disph_m3s
FROM d_hid_t as a
LEFT JOIN disph as b
ON a.id_rank = b.id_rank
AND (SELECT max(b.disph_m3s) WHERE a.dem_hid_m3s <= b.disph_m3s)
A pretty simply method uses distinct on. I might use it before joining:
SELECT h.*, d.*
FROM d_hid_t h LEFT JOIN
(SELECT DISTINCT ON (d.id_rank) d.*
FROM disph d
ORDER BY d.id_rank, disph_m3s DESC
) d
USING (id_rank);
Note the use of meaningful table aliases rather than arbitrary letters.
I need to right join 2 tables with 3 conditions but the resulting table is bigger than left or right table.
left_table a is like the following:
capacity value group_id level_id tags
100 3 a ab
120 5 a afb lala
122 4 b afg hhh
122 6 c adfg
right table b is like the following: bigger than left table
user group_id level_id tags
adsf a ab
af a abf df
sf a afb lala
dsf b afg hhh
sdf c adfg
I want to append the value and capacity value to the right table b. I have used the following query but the resulting table is larger than the right table. I noticed that it is due to the NULL in tags in both the right and left tables, but i am wondering how to resolve this issue.
select a.capacity, a.value, b.*
from a
right join b
on a.group_id = b._group_id
and a.level_id = b.level_id
and a.tags = b.tags
I noticed that it is due to the NULL in tags in both the right and left tables
No, this is not the cause of duplicates. In fact NULL values fail the comparison, so you will not get a match at all if either value is NULL. That is, the row in b will be returned with NULL values for the columns from a.
If you want NULL values to match as being equal, then you need a NULL-safe comparison -- and Presto supports the SQL Standard is not distinct from. I also strongly prefer left join over right join:
select a.capacity, a.value, b.*
from b left join
a
on a.group_id = b._group_id and
a.level_id = b.level_id and
a.tags is not distinct from b.tags;
If you are getting duplicates, it is because you have duplicates in a. You can check for this using:
select group_id, level_id, tags, count(*)
from a
group by group_id, level_id, tags
having count(*) >= 2;
The problem which I am having is joining two tables. One table contains all the generic data and the second table contains old fields which have been given specific values. The exemplary tables below should help to clarify my setup.
Table 1 (Generic Data)
ParaIndex ParaName ParaDefault
1 Cat 15
2 Fish 8
3 Dog 3
Table 2 (Specific Data)
Project ParaIndex ParaValue
John 1 6
John 2 7
Alan 3 9
The goal then is to join these tables to get a single table:
Table 3 (Table Join on ParaIndex for 'John')
ParaName ParaIndex ParaValue ParaDefault
Cat 1 6 15
Fish 2 7 8
Dog 3 3
So Table 3 would return all rows from Table 1 but would only show values for ParaValue where they are not empty. E What I have tried so far is a combination of changing the join type, distinct select, group by, select subqueries, and suggestions mentioned in other posts.
The end goal is then to use this query in vb.net as par of a form.
The closest which I have gotten is to return the requested data in table 3, but it would exclude rows which are not requested (e.g. if the query is for 'John' it would then exclude the parameters marked by 'Alan' which is 3-Dog in this case).
SELECT t1.ParaName, t1.ParaIndex, t2.ParaValue, t1.ParaDefault
FROM Table1 AS t1LEFT OUTER JOIN Table2 AS t2
ON t1.ParaIndex = t2.ParaIndex
WHERE (((t2.ParaIndex) is null) OR t2.Project = 'John')
You have to use a LEFT OUTER JOIN:
SELECT t1.ParaName,
t1.ParaIndex,
COALESCE(CAST(t2.ParaValue AS VARCHAR(10), '') AS ParaValue,
t1.ParaDefaule,
FROM dbo.Table1 t1
LEFT OUTER JOIN dbo.Table2 t2
ON t1.ParaIndex = t2.ParaIndex
WHERE t2.Project = 'John'
ORDER BY t1.ParaIndex
I have a simple SQL query I just get to work out right. I've put together a test database like this;
TABLE MAIN
id name groupone grouptwo
1 Fred 1 3
2 bob 2 1
TABLE DETAIL
id group groupname
1 1 onegrp
2 2 twogrp
4 3 threegrp
My Select query is;
SELECT name, groupone, grouptwo, groupname
FROM main
INNER JOIN detail
ON main.groupone = detail.group
WHERE main.id = 1
The result I get is;
id name groupone grouptwo groupname
1 fred 1 3 onegrp
How do I change this to instead of giving the result as 1 and 3.
I get ... fred onegrp, threegrp
I've tried a dozen things but can't get it to work, I sort of want a give me the groupname again option but not sure what the syntax is for that! :(
Thanks in advance for your time and help
I think this is what you are after. You need to join the detail table twice, on the two different keys.
SELECT
m.Name
,a.groupname as 'GroupOne'
,b.groupname as 'GroupTwo'
FROM
main m
INNER JOIN
detail a
on m.groupone = a.group
INNER JOIN
detail b
on m.grouptwo = b.group
WHERE
m.id = 1
My question is quite similar to Restricting a LEFT JOIN, with a variation.
Assuming I have a table SHOP and another table LOCATION. Location is a sort of child table of table SHOP, that has two columns of interest, one is a Division Key (calling it just KEY) and a "SHOP" number. This matches to the Number "NO" in table SHOP.
I tried this left outer join:
SELECT S.NO, L.KEY
FROM SHOP S
LEFT OUTER JOIN LOCATN L ON S.NO = L.SHOP
but I'm getting a lot of duplicates since there are many locations that belong to a single shop. I want to eliminate them and just get a list of "shop, key" entries without duplicates.
The data is correct but duplicates appear as follows:
SHOP KEY
1 XXX
1 XXX
2 YYY
3 ZZZ
3 ZZZ etc.
I would like the data to appear like this instead:
SHOP KEY
1 XXX
2 YYY
3 ZZZ etc.
SHOP table:
NO
1
2
3
LOCATION table:
LOCATION SHOP KEY
L-1 1 XXX
L-2 1 XXX
L-3 2 YYY
L-4 3 YYY
L-5 3 YYY
(ORACLE 10g Database)
You need to GROUP BY 'S.No' & 'L.KEY'
SELECT S.NO, L.KEY
FROM SHOP S
LEFT OUTER JOIN LOCATN L
ON S.NO = L.SHOP
GROUP BY S.NO, L.KEY
EDIT Following the update in your scenario
I think you should be able to do this with a simple sub query (though I haven't tested this against an Oracle database). Something like the following
UPDATE shop s
SET divnkey = (SELECT DISTINCT L.KEY FROM LOCATN L WHERE S.NO = L.SHOP)
The above will raise an error in the event of a shop being associated with locations that are in multiple divisions.
If you just want to ignore this possibility and select an arbitrary one in that event you could use
UPDATE shop s
SET divnkey = (SELECT MAX(L.KEY) FROM LOCATN L WHERE S.NO = L.SHOP)
I had this problem too but I couldn't use GROUP BY to fix it because I was also returning TEXT type fields. (Same goes for using DISTINCT).
This code gave me duplicates:
select mx.*, case isnull(ty.ty_id,0) when 0 then 'N' else 'Y' end as inuse
from master_x mx
left outer join thing_y ty on mx.rpt_id = ty.rpt_id
I fixed it by rewriting it thusly:
select mx.*,
case when exists (select 1 from thing_y ty where mx.rpt_id = ty.rpt_id) then 'Y' else 'N' end as inuse
from master_x mx
As you can see I didn't care about the data within the 2nd table (thing_y), just whether there was greater than zero matches on the rpt_id within it. (FYI: rpt_id was also not the primary key on the 1st table, master_x).