I am having a problem to resolve a SELECT CASE using TOP.
Should I mention I'm quite new to this ? :D
Also this is my first post on Stackoverflow. Hi !
I want to fill one column of informations from two tables :
Table 1 : Column 1 contains data I want to use
Table 1 : Column 2 is a join
Table 2 : Column 1 contains data I want to use
Table 2 : Column 2 is a join
So :
Table 1 Column 1 contains letters (D M and T) and empty spaces.
Table 2 Column 1 contains words ('Rolls' 'Transfers' 'Delivery')
I'm trying to fill my column using the following conditions :
When column T1.C1 contains D, M or T, write D M or T.
When column T1.C1 is empty, look at column T2.C1 :
If column T1.C1 contains 'Rolls', write 'R'
Else don't write anything
Things get ugly really fast for me because the info I want from column B requires a TOP to be used.
THe best I could get so far is Incorrect syntax near the keyword 'From'.
Here is my code so far.
Any suggestions ?
SELECT
(CASE T1.C1
WHEN 'D'
THEN 'D'
WHEN 'M'
THEN 'M'
WHEN 'T'
THEN 'T'
WHEN (SELECT TOP 1 T2.C1 FROM T2 WHERE T1.C2=T2.C2)
THEN 'R'
ELSE
''
END) as my_data,
FROM T1
I think you should try to find a simpler way to write this, something along the lines of:
WITH cte
AS ( SELECT C1 ,
C2 ,
ROW_NUMBER() OVER ( PARTITION BY C2 ORDER BY col ) rn
FROM Table2
)
SELECT CASE WHEN T1.C1 = '' THEN LEFT(T2.C1, 1)
ELSE T1.C1
END AS my_data
FROM Table1 T1
LEFT OUTER JOIN cte T2 ON T1.C2 = T2.C2
AND T2.rn = 1
You haven't posted your table schema, so this may need to be adjusted.
Related
I'm trying to create a recursive CTE that traverses all the records for a given ID, and does some operations between ordered records. Let's say I have customers at a bank who get charged a uniquely identifiable fee, and a customer can pay that fee in any number of installments:
WITH recursive payments (
id
, index
, fees_paid
, fees_owed
)
AS (
SELECT id
, index
, fees_paid
, fee_charged
FROM table
WHERE index = 1
UNION ALL
SELECT t.id
, t.index
, t.fees_paid
, p.fees_owed - p.fees_paid
FROM table t
JOIN payments p
ON t.id = p.id
AND t.index = p.index + 1
)
SELECT *
FROM payments
ORDER BY 1,2;
The join logic seems sound, but when I join the output of this query to the source table, I'm getting non-deterministic and incorrect results.
This is my first foray into Snowflake's recursive CTEs. What am I missing in the intermediate result logic that is leading to the non-determinism here?
I assume this is edited code, because in the anchor of you CTE you select the fourth column fee_charged which does not exist, and then in the recursion you don't sum the fees paid and other stuff, basically you logic seems rather strange.
So creating some random data, that has two different id streams to recurse over:
create or replace table data (id number, index number, val text);
insert into data
select * from values (1,1,'a'),(2,1,'b')
,(1,2,'c'), (2,2,'d')
,(1,3,'e'), (2,3,'f')
v(id, index, val);
Now altering you CTE just a little bit to concat that strings together..
WITH RECURSIVE payments AS
(
SELECT id
, index
, val
FROM data
WHERE index = 1
UNION ALL
SELECT t.id
, t.index
, p.val || t.val as val
FROM data t
JOIN payments p
ON t.id = p.id
AND t.index = p.index + 1
)
SELECT *
FROM payments
ORDER BY 1,2;
we get:
ID INDEX VAL
1 1 a
1 2 ac
1 3 ace
2 1 b
2 2 bd
2 3 bdf
Which is exactly as I would expect. So how this relates to your "it gets strange when I join to other stuff" is ether, your output of you CTE is not how you expect it to be.. Or your join to other stuff is not working as you expect, Or there is a bug with snowflake.
Which all comes down to, if the CTE results are exactly what you expect, create a table and join that to your other table, so eliminate some form of CTE vs JOIN bug, and to debug why your join is not working.
But if your CTE output is not what you expect, then lets help debug that.
Basically I want COUNT a CASE when values are present in 2 columns.
For example:
SELECT
COUNT
(CASE WHEN 1.sample AND 2.sample IN ('a','b','c')
THEN 1
ELSE NULL
END
) AS CASE
FROM table1 AS 1
INNER JOIN table2 AS 2
...
Message:
Conversion failed when converting the varchar value '08:12.06' to data
type int. Warning: Null value is eliminated by an aggregate or other
SET operation.
I get what's triggering the error, I just don't know a solution to count the case when values are present in both columns.
Can you try this and see if it works? I think this is what you are looking for.
SELECT
SUM
(CASE WHEN 1.sample IN ('a','b','c') AND 2.sample IN ('a','b','c')
THEN 1
ELSE 0
END
) AS CASE
FROM table1 AS 1
INNER JOIN table2 AS 2
You need to list the columns separately for comparison. Usually I specify a column to count, and you do not need to put NULL for the else condition.
SELECT
COUNT
(CASE WHEN 1.sample IS NULL OR 2.sample IS NULL THEN 0
WHEN ( 1.sample IN ('a','b','c')
AND 2.sample IN ('a','b','c')
)
THEN 1.sample
END
) AS CASE
FROM table1 AS 1
INNER JOIN table2 AS 2 ON....
This is my first post - so I apologise if it's in the wrong seciton!
I'm joining two tables with a one-to-many relationship using their respective ID numbers: but I only want to return the most recent record for the joined table and I'm not entirely sure where to even start!
My original code for returning everything is shown below:
SELECT table_DATES.[date-ID], *
FROM table_CORE LEFT JOIN table_DATES ON [table_CORE].[core-ID] = table_DATES.[date-ID]
WHERE table_CORE.[core-ID] Like '*'
ORDER BY [table_CORE].[core-ID], [table_DATES].[iteration];
This returns a group of records: showing every matching ID between table_CORE and table_DATES:
table_CORE date-ID iteration
1 1 1
1 1 2
1 1 3
2 2 1
2 2 2
3 3 1
4 4 1
But I need to return only the date with the maximum value in the "iteration" field as shown below
table_CORE date-ID iteration Additional data
1 1 3 MoreInfo
2 2 2 MoreInfo
3 3 1 MoreInfo
4 4 1 MoreInfo
I really don't even know where to start - obviously it's going to be a JOIN query of some sort - but I'm not sure how to get the subquery to return only the highest iteration for each item in table 2's ID field?
Hope that makes sense - I'll reword if it comes to it!
--edit--
I'm wondering how to integrate that when I'm needing all the fields from table 1 (table_CORE in this case) and all the fields from table2 (table_DATES) joined as well?
Both tables have additional fields that will need to be merged.
I'm pretty sure I can just add the fields into the "SELECT" and "GROUP BY" clauses, but there are around 40 fields altogether (and typing all of them will be tedious!)
Try using the MAX aggregate function like this with a GROUP BY clause.
SELECT
[ID1],
[ID2],
MAX([iteration])
FROM
table_CORE
LEFT JOIN table_DATES
ON [table_CORE].[core-ID] = table_DATES.[date-ID]
WHERE
table_CORE.[core-ID] Like '*' --LIKE '%something%' ??
GROUP BY
[ID1],
[ID2]
Your example field names don't match your sample query so I'm guessing a little bit.
Just to make sure that I have everything you’re asking for right, I am going to restate some of your question and then answer it.
Your source tables look like this:
table_core:
table_dates:
And your outputs are like this:
Current:
Desired:
In order to make that happen all you need to do is use a subquery (or a CTE) as a “cross-reference” table. (I used temp tables to recreate your data example and _ in place of the - in your column names).
--Loading the example data
create table #table_core
(
core_id int not null
)
create table #table_dates
(
date_id int not null
, iteration int not null
, additional_data varchar(25) null
)
insert into #table_core values (1), (2), (3), (4)
insert into #table_dates values (1,1, 'More Info 1'),(1,2, 'More Info 2'),(1,3, 'More Info 3'),(2,1, 'More Info 4'),(2,2, 'More Info 5'),(3,1, 'More Info 6'),(4,1, 'More Info 7')
--select query needed for desired output (using a CTE)
; with iter_max as
(
select td.date_id
, max(td.iteration) as iteration_max
from #table_dates as td
group by td.date_id
)
select tc.*
, td.*
from #table_core as tc
left join iter_max as im on tc.core_id = im.date_id
inner join #table_dates as td on im.date_id = td.date_id
and im.iteration_max = td.iteration
select *
from
(
SELECT table_DATES.[date-ID], *
, row_number() over (partition by table_CORE date-ID order by iteration desc) as rn
FROM table_CORE
LEFT JOIN table_DATES
ON [table_CORE].[core-ID] = table_DATES.[date-ID]
WHERE table_CORE.[core-ID] Like '*'
) tt
where tt.rn = 1
ORDER BY [core-ID]
I do have table were one row (with Type =E) is related to another row.
I have written query to return COUNT of those related rows. The problem is that there is no explicit relationship (like ID column that would clearly say which row is related to other row). Therefore I am trying to find relationship based on multiple conditions in WHERE clause.
The problem is that in few cases, the columns A and B could be NULL (for records where TYPE = 'M'). In such a cases I would like to ignore that condition, so It would use only first 3 conditions to determine relationship.
I have tried CASE Statement but is not working as expected:
SELECT [T1].[ID],[T1].[AlphaId],[T1].[Type],[T1].[A],[T1].[B],[T1].[Date],[T1].[ServiceID]
,( SELECT COUNT(*)
FROM MyTable T2
WHERE [T1].[AlphaId]=[T2].[AlphaId] AND
[T1].[Date]=[T2].[Date] AND
[T1].[ServiceID]=[T2].[ServiceID] AND
[T2].[A]=CASE WHEN [T2].[A] IS NULL THEN NULL ELSE [T1].[A] END AND
[T2].[B]=CASE WHEN [T2].[B] IS NULL THEN NULL ELSE [T1].[B] END AND
[T2].[Type]='M'
) as TotalCount
FROM MyTable T1
WHERE [T1].[Type] = 'E'
I can't ignore that condition, as for some cases the Date, ServiceID could be same, however it's the A, B which differs them. Luckily where A, B IS NULL, it is the Date, ServiceID which differs those two records.
http://sqlfiddle.com/#!3/c98db/1
Many thanks in advance.
You could join the tables and use COUNT and GROUP BY to get the counts. Then you can JOIN [A] and [B] if they are equal or NULL.
SELECT [T1].[ID],[T1].[AlphaId],[T1].[Type],[T1].[A],[T1].[B],[T1].[Date],[T1].[ServiceID], count([T2].[ID])
FROM MyTable T1
INNER JOIN MyTable T2 ON [T1].[AlphaId]=[T2].[AlphaId] AND
[T1].[Date]=[T2].[Date] AND
[T1].[ServiceID]=[T2].[ServiceID] AND
([T2].[A]= [T1].[A] OR [T2].[A] IS NULL )AND
([T2].[B]= [T1].[B] OR [T2].[B] IS NULL )AND
[T2].[Type] <> [T1].[Type]
WHERE [T1].[Type] = 'E'
GROUP BY [T1].[ID],[T1].[AlphaId],[T1].[Type],[T1].[A],[T1].[B],[T1].[Date],[T1].[ServiceID]
I'm having trouble figuring this out.
According to Jeff Atwood A Visual Explanation of SQL Joins Left outer join produces a complete set of records from Table A, with the matching records (where available) in Table B. If there is no match, the right side will contain null.
The left table (TableA) doesn't have duplicates. The right tableB has 1 or 2 entries for each client number. The PrimaryTP designates one as primary with 1 and the other has 0.
I shouldn't have to include the line And B.PrimaryTP = 1 because TableA doesn't have duplicates. Yet if I leave it out I get duplicate client numbers. Why?
Can you help me understand how this works. It's being very confusing to me. The logic of And B.PrimaryTP = 1 escapes me. Yet it seems to work. Still, I'm scared to trust it if I don't understand it. Can you help me understand it. Or do I have a logic error hidden in the query?
SELECT A.ClientNum --returns a list with no duplicate client numbers
FROM (...<TableA>
) as A
Left Outer Join
<TableB> as B
on A.ClientNum = B.ClientNum
--eliminate mismatch of (ClientNum <> FolderNum)
Where A.ClientNum Not In
(
Select ClientNum From <TableB>
Where ClientNum Is Not Null
And ClientNum <> IsNull(FolderNum, '')
)
--eliminate case where B.PrimaryTP <> 1
And B.PrimaryTP = 1
The difference between an INNER JOIN and a LEFT JOIN is just that the LEFT JOIN still returns the rows in Table A when there are no corresponding rows in Table B.
But it's still a JOIN, which means that if there is more than one corresponding row in Table B, it will join the row from Table A to each one of them.
So if you want to make sure that you get no more than one result for each row in Table A, you have to make sure that no more than one row from Table B is found - hence the And B.PrimaryTP = 1.
If you have one client number in A and two matches in Table B, then you will get duplicates.
Suppose you have the following data,
Table-A(client Num) Table-B(client Num)
1 2
2 2
The left Join Results
Table-A(client Num) Table-B(client Num)
1 (null)
2 2
2 2
This is the cause of duplicates. So you need to take distinct values form Table B or perform Distinct on the result set.
I shouldn't have to include the line And B.PrimaryTP = 1 because TableA doesn't have duplicates. Yet if I leave it out I get duplicate client numbers. Why?
Because both rows in the right table match a row in the left table. There is no way for SQL Server to output a triangular result; it must show the columns from both tables for every joined row. And this is true for INNER JOIN as well.
DECLARE #a TABLE(a INT);
DECLARE #b TABLE(b INT);
INSERT #a VALUES(1),(2);
INSERT #b VALUES(1),(1);
SELECT a.a, b.b FROM #a AS a
LEFT OUTER JOIN #b AS b ON a.a = b.b;
SELECT a.a, b.b FROM #a AS a
INNER JOIN #b AS b ON a.a = b.b;
Results:
a b
-- ----
1 1
1 1
2 NULL
a b
-- --
1 1
1 1
On the link that you gave the joins are explained very good. So the problem is that you have several records from table A (no matter that there are no duplicates) is that to 1 record in A there are 2 records in B (in some cases). To avoid this you can use either DISTINCT clause, either GROUP BY clause.
The LEFT OUTER JOIN will give you all the records from A with all the matching records from B. The difference with an INNER JOIN is that if there are no matching records in B, an INNER join will omit the record from A entirely, while the LEFT join will then still include a row with the results from A.
In your case, however, you may also want to check out the DISTINCT keyword.