In my sql script LEFT JOIN is giving output like CROSS JOIN? - sql

I have two table like following
DailyData
Date Id CompanyName CompanyPrice CompanyId
21-12-2011 123 ABC corp 120 535
25-12-2011 352 Z Edge 101 444
25-12-2011 352 Z Edge 100 444
primary key is `date` and `Id`
ReportData
RId Date CompanyName TodayPrice CompanyId
1 25-12-2011 Z Edge 230 444
primary key is only `RId`
Now I have used following LEFT JOIN on both above table like :
Select a.date,a.companyname,a.CompanyPrice,b.TodayPrice
from DailyData a LEFT JOIN ReportData b ON
a.companyid= b.companyid where a.Date = '25-12-2011'
But instead of two records it is giving more than two records (same records multiple times)
Why is it so ?
Please help me to correct my sql query.
expected output for above data should be:
date companyname companyprice todaysprice
25-12-2011 Z Edge 101 230
25-12-2011 Z Edge 100 230

You current query is missing a JOIN on the actual columns, as a result you are getting a CROSS JOIN result of all the rows that meet the date condition. You will want to use:
Select a.date,a.companyname,a.CompanyPrice,b.TodayPrice
from DailyData a
LEFT JOIN ReportData b
ON a.CompanyId= b.CompanyId
WHERE a.Date = '25-12-2011';
See SQL Fiddle with Demo

Your Join condition: [ ON a.Date = '25-12-2011' ] does not establish any condition on table b, therefore, every row in table b is joined to each row in table a with that specified date.
From looking at the two tables it is not obvious whether the they should be joined on date or on CompanyID.

I believe you need something like
Select a.date,a.companyname,a.CompanyPrice,b.TodayPrice
from DailyData a
LEFT JOIN ReportData b ON
(b.CompanyId = a.CompanyId )
WHERE a.Date = '25-12-2011'

sql fiddle
no LEFT and no WHERE clause
Select a.date,
a.companyname,a.CompanyPrice,b.TodayPrice
from DailyData a
JOIN ReportData b
ON a.CompanyId= b.CompanyId

Related

SQL/Presto: right join bigger than original table due to NULL

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;

How to fix sql query problem with two or more position which have one ID

I have sql query where I have to join three tables. One of this is a table with data of invoice, it looks like this:
INVOICE
ID CUSTOMER_NAME TAXID NUMBER LABEL GUID
1 CUSTOMER1 8739281100 FV001/2019 1 04EABFB3-0B9D-4749-B99D-A4EBEE079633
POSITION OF INVOICE
ID ID_INV POSITION_NAME COUNT
1 1 NAME1 3
2 1 NAME2 2,5
TABLE WITH LABEL
ID NAME VALUE GUID_INV
1 LABEL1 true 04EABFB3-0B9D-4749-B99D-A4EBEE079633
When I want to run this query I have statement like this multiple rows in singleton select.
This is for Firebird 2.5.
SELECT
a.ID,
a.GUID,
a.NUMBER,
a.CUSTOMER_NAME,
b.COUNT,
(select usrd.LABEL from USER_FIELD_DEFS usrd
where usrd.GUID_INV=a.GUID and (usrd.ID=1 and usrb.VALUE='true')) as LABEL_NAME
FROM INVOICE a
join POSITION_INVOICE b ON a.ID=b.ID_INV
I want to get result like this
1 04EABFB3-0B9D-4749-B99D-A4EBEE079633 FV001/2019 CUSTOMER1 3 LABEL1
1 04EABFB3-0B9D-4749-B99D-A4EBEE079633 FV001/2019 CUSTOMER1 2,5 LABEL1
Please help with this. I know that solution maybe is very simple but I have some eclipse of the mind:)
This should give you the rows you want based on the 3 tables you provided. If there is a chance that an invoice has no position then simply replace the inner join with left join
SELECT
I.[Id]
,I.[GUID]
,I.[NUMBER]
,I.[CUSTOMER_NAME]
,IP.[POSITION_NAME]
,L.[NAME]
FROM [INVOICE] I
INNER JOIN [IN_P] IP ON IP.ID_INV = I.Id
LEFT JOIN [LABEL] L ON L.[GUID_INV] = I.[GUID]
You are just missing one more join here. Assuming USER_FIELD_DEFS is the same as TABLE WITH LABEL that you have mentioned here
SELECT
a.ID,
a.GUID,
a.NUMBER,
a.CUSTOMER_NAME,
b.COUNT,
c.NAME
FROM INVOICE a
JOIN POSITION_INVOICE b ON a.ID=b.ID_INV
JOIN USER_FIELD_DEFS c ON c.GUID_INV = a.GUID AND c.ID=1 and c.VALUE='true'

JOIN query, SQL Server is dropping some rows of my first table

I have two tables customer_details and address_details. I want to display customer details with their corresponding address, so I was using a LEFT JOIN, but when I'm executing this query, SQL Server drops rows where street_no of customer_details table doesn't match with the street_no in address_detials table and displays only rows where `street_no' of customer_detials = street_no of address_details table. I need to display a complete customer_details table and in case if street_no doesn't matches it should display empty string or anything. Am I doing anything wrong in my SQL join?
Table customer_details:
case_id customer_name mob_no street_no
-------------------------------------------------
1 John 242342343 4324234234234
1 Rohan 343233333 43332
1 Ankit 234234233 2342332423433
1 Suresh 234234324 2342342342342
1 Ranjeet 343424323 32233
1 Ramu 234234333 2342342342343
Table address_details:
s_no streen_no address city case_id
------------------------------------------------------
1 4324234234234 Roni road Delhi 1
2 2342332423433 Natan street Lucknow 1
3 2342342342342 Koliko road Herdoi 1
SQL JOIN query:
select
a.*, b.address
from
customer_details a
left join
address_details b on a.street_no = b.street_no
where
b.case_id = 1
Now that it became clear that you used b.case_id=1, I will explain why it filters:
The LEFT JOIN itself returns some rows that contain all NULL values for table b in the result set, which is what you want and expect.
But by using WHERE b.case_id=1, the rows containing NULL values for table b are filtered out because none of them matches the condition (all those rows have b.case_id=NULL so they don't match).
It might work to instead use WHERE a.case_id=1, but we don't know if a.case_id and b.case_id are always the same value for matching rows (they might not be; and if they are always the same, then we just identified a potential redundancy).
There are two ways to fix this for sure.
(1) Move b.case_id = 1 into the left join condition:
left join address_details b on a.street_no = b.street_no and b.case_id = 1
(2) Keep b.case_id = 1 in the WHERE but also allow for NULLED-out b values:
left join address_details b on a.street_no = b.street_no
where b.case_id = 1
or b.street_no IS NULL
Personally I'd go for (1) because that is the most clear way to express that you want to filter b on two conditions, without affecting the rows of a that are being returned.
I do think that Wilhelm Poggenpohl answer is kind of right. You just need to change the last join condition a.case_id=1 to b.case_id=1
select a.* , b.address
from customer_details a
left join address_details b on a.street_no=b.street_no
and b.case_id=1
This query will show every row from customer_details and the corresponding adress if there is a match of street_no and the adress meets the condition case_id=1.
This is because of the where clause. Try this:
select a.* , b.address
from customer_details a
left join address_details b on a.street_no=b.street_no
and a.case_id=1

Grouping the data and showing 1 row per group in postgres

I have two tables which look like this :-
Component Table
Revision Table
I want to get the name,model_id,rev_id from this table such that the result set has the data like shown below :-
name model_id rev_id created_at
ABC 1234 2 23456
ABC 5678 2 10001
XYZ 4567
Here the data is grouped by name,model_id and only 1 data for each group is shown which has the highest value of created_at.
I am using the below query but it is giving me incorrect result.
SELECT cm.name,cm.model_id,r.created_at from dummy.component cm
left join dummy.revision r on cm.model_id=r.model_id
group by cm.name,cm.model_id,r.created_at
ORDER BY cm.name asc,
r.created_at DESC;
Result :-
Anyone's help will be highly appreciated.
use max and sub-query
select T1.name,T1.model_id,r.rev_id,T1.created_at from
(
select cm.name,
cm.model_id,
MAX(r.created_at) As created_at from dummy.component cm
left join dummy.revision r on cm.model_id=r.model_id
group by cm.name,cm.model_id
) T1
left join revision r
on T1.created_at =r.created_at
http://www.sqlfiddle.com/#!17/68cb5/4
name model_id rev_id created_at
ABC 1234 2 23456
ABC 5678 2 10001
xyz 4567
In your SELECT you're missing rev_id
Try this:
SELECT
cm.name,
cm.model_id,
MAX(r.rev_id) AS rev_id,
MAX(r.created_at) As created_at
from dummy.component cm
left join dummy.revision r on cm.model_id=r.model_id
group by 1,2
ORDER BY cm.name asc,
r.created_at DESC;
What you were missing is the statement to say you only want the max record from the join table. So you need to join records, but the join will bring in all records from table r. If you group by the 2 columns in component, then select the max from r, on the id and created date, it'll only pick the top out the available to join
I would use distinct on:
select distinct on (m.id) m.id, m.name, r.rev_id, r.created_at
from model m left join
revision r
on m.model_id = r.model_id
order by m.id, r.rev_id;

Oracle, LEFT OUTER JOIN not returning all rows from left table, instead behaving like INNER JOIN

I'm doing a left outer join and only getting back matching rows like it was an inner join.
To simplify the data, my first table(ROW_SEG), or left table looks something like this:
ASN | DEPT NO
-----------------------
85 | 836
86 | null
87 | null
My second table(RF_MERCHANT_ORG) has DEPT_NAME, and some other things which i want to get when i have a dept number.
DEPT NO | DEPT_NAME
-----------------------
836 | some dept name 1
837 | some dept name 2
838 | some dept name 3
In this case after my join i'd only get 1 row, for ASN 85 that had a DEPT NO.
...omitting a bunch of SQL for simplicity
, ROW_SEG AS (
SELECT *
FROM VE_SI_EC_OI
WHERE ROW_NUM BETWEEN 1 AND 1000 -- screen pagination, hardcoding values
)
-- ROW_SEG has a count of 1000 now
, RFS_JOIN AS (
SELECT ROW_SEG.*
,MO.BYR_NO
,MO.BYR_NAME
,MO.DEPT_NAME
FROM ROW_SEG
LEFT OUTER JOIN RF_MERCHANT_ORG MO
ON ROW_SEG.DEPT_NO = MO.DEPT_NO
WHERE MO.ORG_NO = 100
)
SELECT * FROM RFS_JOIN; -- returns less than 1000
I only get back the number of rows equal to the number of rows that have dept nos. So in my little data example above i would only get 1 row for ASN 85, but i want all rows with BYR_NO, BYR_NAME, AND DEPT_NAME populated on rows where i had a DEPT_NO, and if not, then empty/null columns.
If ORG_NO is within the RF_MERCHANT_ORG table (using aliases consistently would help there) then acting like an inner join would then would be the correct result for the SQL being used.
The join should be this to make it act like a proper left join:
LEFT OUTER JOIN RF_MERCHANT_ORG MO ON ROW_SEG.DEPT_NO = MO.DEPT_NO AND MO.ORG_NO = 100
If ORG_NO is in RF_MERCHANGE_ORG, then that is likely to be the cause... the where condition is limiting the result set.