I have the following:
TableA
ID | DocumentType | DocumentCode | DocumentDate | Warehouse | RefecenceCode
---+--------------+--------------+--------------+-----------+--------------
1 | DeliveryNote | DOC-001 | 2017-04-21 | 1 | NULL
2 | Invoice | DOC-002 | 2017-04-21 | 2 | DOC-001
As you can see, the warehouse is different on each document and DOC-002 is related to DOC-001 through the information in ReferenceCode column (which means that was created starting from DOC-001 as a source document).
It is supposed for the DOC-002 to have the same information but sometimes might be different and in this case, I was tried to create a query (I think self join applies here) in order to check what information is different in the DOC-002 in this case compared to DOC-001, based on the reference code, but I couldn't managed to do it.
If someone could give me a hand, I'll be very grateful.
This is the SQL query:
select *
from TableA tbl
inner join TableA tbla on tbl.id = tbla.id
where tbla.ReferenceCode = tbl.DocumentCode
You indeed want to join the table to itself. But joining on the ID column won't work, because that column doesn't relate records to each other. Instead, you need to join on the DocumentCode and ReferenceCode fields. Then only include the records that have some difference (in this case, I'm only comparing the DocumentDate and Warehouse fields).
select tbla.*
from TableA tbl
join TableA tbla on tbl.DocumentCode = tbla.ReferenceCode
where tbla.DocumentDate != tbl.DocumentDate
or tbla.Warehouse != tbl.Warehouse
Related
I have two tables (first two shown) and need to make a third from the first two - do I need to do a join or can you reference a table without joining?
The third table shown is the desired output. Thanks for any help!
| ACC | CALL DATE | | |
+-----+-----------+--+--+
| 1 1 | 2/1/18 | | |
+-----+-----------+--
+-----+---------------+--+--+
| ACC | PURCHASE DATE | | |
+-----+---------------+--+--+
| 1 1 | 1/1/18 | | |
+-----+---------------+--+--+
+-----+-----------+----------------------+--+
| ACC | CALL DATE | PRIOR MONTH PURCHASE | |
+-----+-----------+----------------------+--+
| 1 1 | 2/1/18 | YES | |
+-----+-----------+----------------------+--+
Of course you can have a query that references multiple tables without joining. union all is an example of an operator that does that.
There is also the question of what you mean by "joining" in the question. If you mean explicit joins, there are ways around that -- such as correlated subqueries. However, these are implementing some form of "join" in the database engine.
As for your query, you would want to use exists with a correlated subquery:
select t1.*,
(case when exists (select 1
from table2 t2
where t2.acc = t1.acc and
datediff(month, t2.purchase_date, t1.call_date) = 1
)
then 'Yes' else 'No'
end) as prior_month_purchase
from table1 t1;
This is "better" than a join because it does not multiply or remove rows. The result set has exactly the rows in the first table, with the additional column.
The syntax assumes SQL Server (which was an original tag). Similar logic can be expressed in other databases, although date functions are notoriously database-dependent.
Lets check the options,
Say if you were to create a new third table on the basis of the data in first two, then every update/inserts/deletes to either of the tables should also propagate into the third table as well.
Say you instead have a view which does what you need, there isnt a need to maintain that third table and also gets you the data needed from the first two each time you query it.
create view third_table as
select a.acc,a.call_date,case when dateadd(mm,-1,a.call_date)=b.purchase_date then 'Yes' else 'No end as prior_month_purchase
from first_table a
left join second_table b
on a.acc=b.acc
I have two tables
Calendar (Calname, CCode, PCode)
Lookup (LCode, Name)
Calendar table contains records like,
Calname | CCode | PCode
abc | O_R | P_R
xyz | C_R | P_C
Lookup table contains records like,
LCode | Name
O_R | Reporting
C_R | Cross
P_R | Process
P_C | ProcessCross
I have to fetch the records in a way where I can get the name of all codes from lookup table which contains the record rowwise.
Desired Output,
Calname | CCode | PCode | CCodeName | PCodeName
abc | O_R | P_R | Reporting | Process
xyz | C_R | P_C | Cross | ProcessCross
I can not apply simply inner join on the basis of code it will not give me desired output.
I tried to use subquery also but it not worked out somehow,
.
Can anyone help me out with this issue.
Thanks
You can try joining the Calendar table to the Lookup table twice, using each of the two codes.
SELECT
c.Calname,
c.CCode,
c.PCode,
COALESCE(t1.Name, 'NA') AS CCodeName,
COALESCE(t2.Name, 'NA') AS PCodeName
FROM Calendar c
LEFT JOIN Lookup t1
ON c.CCode = t1.LCode
LEFT JOIN Lookup t2
ON c.PCode = t2.LCode
An alternative to Tim's answer would be to use scalar subqueries, which may or may not give you some performance benefit due to scalar subquery caching:
SELECT
c.Calname,
c.CCode,
c.PCode,
COALESCE((SELECT l1.name FROM lookup l1 WHERE c.ccode = l1.lcode), 'NA') AS CCodeName,
COALESCE((SELECT l2.name FROM lookup l2 WHERE c.pcode = l2.lcode), 'NA') AS PCodeName
FROM Calendar c;
I would test both answers to see which one works best for your data.
OK. So this is a hard one to explain, but I am replacing the type of a foreign key in a database. To do this I need to update the values in a table that references it. That is all fine and good, and nice and easy to do.
I'm inserting this stuff into a temporary table which will replace the original table, but the insert query isn't at all difficult, it's the select that I get the values from.
However, I also want to keep any entries where the original reference was NULL. Also not hard, I could use a Left Inner Join for that.
But we're not done yet: I don't want the entries for which there is no match in the second table. I've been dinking around with this for 2 hours now, and am no closer to figuring this out than I am to the moon.
Let me give you an example data set:
____________________________
| Inventory || Customer |
|============||============|
| ID Cust || ID Name |
|------------||------------|
| 1 A || 1 A |
| 2 B || 2 B |
| 3 E || 3 C |
| 4 NULL || 4 D |
|____________||____________|
Let's say the database used to use the Customer.Name field as its Primary Key, and I need to change it to a standard int identity(1,1) not null ID. I've added the field with no issues in the Customer table, and kept the Name because I need it for other stuff. I have had no trouble with this in all the tables that do not allow NULLs, but since the "Inventory" table allows something to be associated with No customer, I'm running into troubles.
If I did a left inner join, my results would be:
______________
| Results |
|============|
| ID Cust |
|------------|
| 1 1 |
| 2 2 |
| 3 NULL |
| 4 NULL |
|____________|
However, Inventory #3 was referencing a customer which does not exist. I want that to be filtered out.
This database is my development database, where I hack, slash, and destroy things with wanton disregard for validity. So a lot of links in these tables are no longer valid.
The next step is replicating this process in the beta-testing environment, where bad records shouldn't exist, but I can't guarantee that. So I'd like to keep the filter, if possible.
The query I have right now is using a sub-query to find all rows in Inventory whose CustID either exists in Customers, or is null. It then tries to only grab the value from those rows which the subquery found. Here's the translated query:
insert into results
(
ID,
Cust
)
select
inv.ID, cust.ID
from Inventory inv, Customer cust
where inv.ID in
(
select inv.ID from Inventory inv, Customer cust
where inv.Cust is null
or cust.Name = inv.Cust
)
and cust.Name = inv.Cust
But, as I'm sure you can see, this query isn't right. I've tried using 2, 3 subqueries, inner joins, left joins, bleh. The results of this query, and many others I've tried (that weren't horribly, horribly wrong) are:
______________
| Results |
|============|
| ID Cust |
|------------|
| 1 1 |
| 2 2 |
|____________|
Which is essentially an inner-join. Considering my actual data has around 1100 records which have NULL values in that field, I don't think truncating them is the answer.
The answer I'm looking for is:
______________
| Results |
|============|
| ID Cust |
|------------|
| 1 1 |
| 2 2 |
| 4 NULL |
|____________|
The trickiest part of this insert into select is the fact that I'm looking to insert either a value from another table, or essentially a value from this table or the literal NULL. That just isn't something I know how to do; I'm still getting the hang of SQL.
Since I'm inserting the results of this query into a table, I've considered doing the insert using a select which leaves out the NULL values and un-matched records, then going back through and adding in all the NULL records, but I really want to learn how to do the more advanced queries like this.
So do any of yous folks have any ideas? 'Cause I'm lost.
How about a union?
Select all records where ID and Cust match and union that with all records where ID matches and inventory.cust is null.
I have two tables like this.
Table1
Column | Type |
---------+------------------+
cod | text |
value99 | double precision |
Table2
Column | Type |
---------+------------------+
cod | text |
value06 | double precision |
and i'd like to join them so i'd have something like
Column | Type |
---------+------------------+
cod | text |
value99 | double precision |
value06 | double precision |
the problem is that not all the codes are present in both tables, so if a code is not present in one of the tables it's value should be null.. In the end i'd like something like this
cod | value99 | value06 |
---------+------------------+------------------+
1 | 10 | 20 |
2 | 13 | NULL |
3 | NULL | 15 |
I think that its not possible using LEFT or RIGHT JOIN.. or maybe it is... any ideas? Thx=)
EDITED:
I've tried the FULL OUTER JOIN but the result is something like
code value code value
1 10 1 4
2 15 NULL NULL
NULL NULL 3 36
ANSWER!!!:
i found the answer thx to #Tobiasopdenbrouw :
SELECT test1.code,test1.value,test2.value FROM public.test1 LEFT OUTER JOIN public.test2 ON test1.code=test2.code
UNION
SELECT test2.code,test1.value,test2.value FROM public.test1 RIGHT OUTER JOIN public.test2 ON test1.code=test2.code
I'm guessing a bit, because your question doesn't describe the required output in great detail, but what you probably need is a helper query that will create a table with all the codes for you (a UNION of 2 SELECT querys). This helper table can then be LEFT JOINED to your 2 source tables).
Edit: I thought of the (FULL) OUTER JOIN answer myself, but in reading between the lines, I don't think that's what the OP really needs. But I can be wrong, of course.
Use a FULL OUTER JOIN.
Using Full Outer Joins
To retain the
nonmatching information by including
nonmatching rows in the results of a
join, use a full outer join. SQL
Server provides the full outer join
operator, FULL OUTER JOIN, which
includes all rows from both tables,
regardless of whether or not the other
table has a matching value.
Consider a join of the Product table
and the SalesOrderDetail table on
their ProductID columns. The results
show only the Products that have sales
orders on them. The ISO FULL OUTER
JOIN operator indicates that all rows
from both tables are to be included in
the results, regardless of whether
there is matching data in the tables.
You can include a WHERE clause with a
full outer join to return only the
rows where there is no matching data
between the tables. The following
query returns only those products that
have no matching sales orders, as well
as those sales orders that are not
matched to a product (although all
sales orders, in this case, are
matched to a product).
select
coalesce(t1.cod, t2.cod)
,t1.value99
,t2.value06
from
table1 t1
full outer join table2 t2 on t1.cod= t2.cod
I have two tables with a variable amount of columns. (I don't know how many columns or what there names will be) for example Table A and Table B.
TableA:
ID | B_ID | {variable}
TableB
ID | {variable}
Query:
SELECT TableA.*, TableB.* FROM TableA INNER JOIN TableB ON TableA.B_ID= TableB.id;
When TableA and TableB both have a column with a same name I can't distinguish between the two different columns. For example of both tables has the column "Name" this query would result in :
ID | ID | B_ID | NAME | NAME |
1 | 35 | 35 | bob | jim |
What I am looking for is a way to differentiate between the two tables. Preferably with a prefex for the column names such as.
TableA_ID | TableB_ID | TableA_B_ID | TableA_NAME | TableB_NAME |
1 | 35 | 35 | bob | jim |
I know of the "AS" keyword but the problem is that I don't know what the column names are going to be before hand. (I don't know if TableA or TableB are going to have the column Name)
So my question is
How do you differentiate the columns between the two tables with a INNER JOIN when the tables may have the same column names ?
I am using SQLite3.
Your result set (given your query) should have all of the TableA columns followed by all the TableB colums, so when you get to the second ID colum, you know you're into the TableB data.
That said, it is would seem odd to me that you're querying all the data out of two tables about which you know functionally nothing...
This is admittedly a hack solution, but this:
SELECT TableA.*, "#", TableB.*
FROM TableA INNER JOIN TableB ON TableA.B_ID= TableB.id;
Would produce a list of results which would be divided in two blocks, left and right of the # column.