I need help with a logic in sql
I have two columns
Ticket no. Status
T1 CC
T1 CP
T1 CR
T1 CO
T2 CP
T2 CR
T2 CO
I want to exclude the entire group of Ticket no. that has the status CC. So in this case, after I run the query I should only get 3 records (i.e. T2 records coz T2 doesn’t have a ticket status CC.
Can anyone help me with a simple sql query please.
One method is not exists:
select t.*
from t
where not exists (select 1
from t t2
where t2.ticket_no = t.ticket_no and t2.status = 'CC'
);
In Teradata, though, the qualify clause might be simpler:
select t.*
from t
qualify sum(case when status = 'CC' then 1 else 0 end) over (partition by ticket_no) = 0;
Related
I have a table with 3 values.
ID AuditDateTime UpdateType
12 12-15-2015 18:09 1
45 12-04-2015 17:41 0
75 12-21-2015 04:26 0
12 12-17-2015 07:43 0
35 12-01-2015 05:36 1
45 12-15-2015 04:35 0
I'm trying to return only records where the UpdateType has changed from AuditDateTime based on the IDs. So in this example, ID 12 changes from the 12-15 entry to the 12-17 entry. I would want that record returned. There will be multiple instances of ID 12, and I need all records returned where an ID's UpdateType has changed from its previous entry. I tried adding a row_number but it didn't insert sequentially because the records are not in the table in order. I've done a ton of searching with no luck. Any help would be greatly appreciated.
By using a CTE it is possible to find the previous record based upon the order of the AuditDateTime
WITH CTEData AS
(SELECT ROW_NUMBER() OVER (PARTITION BY ID ORDER BY AuditDateTime) [ROWNUM], *
FROM #tmpTable)
SELECT A.ID, A.AuditDateTime, A.UpdateType
FROM CTEData A INNER JOIN CTEData B
ON (A.ROWNUM - 1) = B.ROWNUM AND
A.ID = B.ID
WHERE A.UpdateType <> B.UpdateType
The Inner Join back onto the CTE will give in one query both the current record (Table Alias A) and previous row (Table Alias B).
This should do what you're trying to do I believe
SELECT
T1.ID,
T1.AuditDateTime,
T1.UpdateType
FROM
dbo.My_Table T1
INNER JOIN dbo.My_Table T2 ON
T2.ID = T1.ID AND
T2.UpdateType <> T1.UpdateType AND
T2.AuditDateTime < T1.AuditDateTime
LEFT OUTER JOIN dbo.My_Table T3 ON
T3.ID = T1.ID AND
T3.AuditDateTime < T1.AuditDateTime AND
T3.AuditDateTime > T2.AuditDateTime
WHERE
T3.ID IS NULL
Alternatively:
SELECT
T1.ID,
T1.AuditDateTime,
T1.UpdateType
FROM
dbo.My_Table T1
INNER JOIN dbo.My_Table T2 ON
T2.ID = T1.ID AND
T2.UpdateType <> T1.UpdateType AND
T2.AuditDateTime < T1.AuditDateTime
WHERE
NOT EXISTS
(
SELECT *
FROM
dbo.My_Table T3
WHERE
T3.ID = T1.ID AND
T3.AuditDateTime < T1.AuditDateTime AND
T3.AuditDateTime > T2.AuditDateTime
)
The basic gist of both queries is that you're looking for rows where an earlier row had a different type and no other rows exist between the two rows (hence, they're sequential). Both queries are logically identical, but might have differing performance.
Also, these queries assume that no two rows will have identical audit times. If that's not the case then you'll need to define what you expect to get when that happens.
You can use the lag() window function to find the previous value for the same ID. Now you can pick only those rows that introduce a change:
select *
from (
select lag(UpdateType) over (
partition by ID
order by AuditDateTime) as prev_updatetype
, *
from YourTable
) sub
where prev_updatetype <> updatetype
Example at SQL Fiddle.
Assume there is a table name "test" below:
name value
n1 1
n2 2
n3 3
Now, I want to get the name which has the max value, I have some solution below:
Solution 1:
SELECT TOP 1 name
FROM test
ORDER BY value DESC
solution 2:
SELECT name
FROM test
WHERE value = (SELECT MAX(value) FROM test);
Now, I hope use join operation to find the result, like
SELECT name
FROM test
INNER JOIN test ON...
Could someone please help and explain how it works?
If you are looking for JOIN then
SELECT T.name, T.value
FROM test T
INNER JOIN
( SELECT T1.name, T1.value ,
RANK() OVER (PARTITION BY T1.name ORDER BY T1.value) N
FROM test T1
WHERE T1.value IN (SELECT MAX(t2.value) FROM test T2)
)T3 ON T3.N = 1 AND T.name = T3.name
FIDDLE DEMO
or
select name, value
from
(
select name, value,
row_number() over(order by value desc) rn
from test
) src
where rn = 1
FIDDLE DEMO
First, note that solutions 1 and 2 could give different results when value is not unique. If in your test data there would be an additional record ('n4', 3), then solution 1 would return either 'n3' or 'n4', but solution 2 would return both.
A solution with JOIN will need aliases for the table, because as you started of, the engine would say Ambiguous column name 'name'.: it would not know whether to take name from the first or second occurrence of the test table.
Here is a way to complete the JOIN version:
SELECT t1.name
FROM test t1
LEFT JOIN test t2
ON t2.value > t1.value
WHERE t2.value IS NULL;
This query takes each of the records, and checks if any records exist that have a higher value. If not, the first record will be in the result. Note the use of LEFT: this denotes an outer join, so that records from t1 that have no match with t2 -- based on the ON condition -- are not immediately rejected (as would be the case with INNER): in fact, we want to reject all the other records, which is done with the WHERE clause.
A way to understand this mechanism, is to look at a variant of the query above, which lacks the WHERE clause and returns the values of both tables:
SELECT t1.value, t2.value
FROM test t1
LEFT JOIN test t2
ON t2.value > t1.value
On your test data this will return:
t1.value t2.value
1 2
1 3
2 3
3 (null)
Note that the last entry would not be there if the join where an INNER JOIN. But with the outer join, one can now look for the NULL values and actually get those records in the result that would be excluded from an INNER JOIN.
Note that this query will give the same result as solution 2 when there are duplicate values. If you want to have also only one result like with solution 1, it suffices to add TOP 1 after SELECT.
Here is a fiddle.
Alternative with pure INNER JOIN
If you really want an INNER join, then this will do it. Again the TOP 1 is only needed if you have non-unique values:
SELECT TOP 1 t1.name
FROM test t1
INNER JOIN (SELECT Max(value) AS value FROM test) t2
ON t2.value = t1.value;
But this one really is very similar to what you did in solution 2. Here is fiddle for it.
I'm having a problem with a particular MySQL query.
I have table1, and table2, table2 is joined onto table1.
Now the problem is that I am joining table2 to table1 with a condition that looks like:
SELECT
table1.*, table2.*
JOIN table2 ON ( table2.table1_id = table1.id
AND ( table2.lang = 'fr'
OR table2.lang = 'eu'
OR table2.lang = 'default') )
I need it to return only 1 row from table2, even though there might exists many table2 rows for the correct table1.id, with many different locales.
I am looking for a way to join only ONE row with a priority of the locales, first check for one where lang = something, then if that doesn't manage to join/return anything, then where lang = somethingelse, and lastly lang = default.
FR, EU can be different for many users, and rows in the database might exist for many different locales.. I need to select the most suitable ones with the correct fallback priority.
I tried doing the query above with a GROUP BY table2.table1_id, and it seemed to work, but I realised that if the best matching (first OR) was entered later in the table (higher primary ID) it would return 2nd or default priority as the grouped by row..
Any tips?
Thank you!
it still doesn't seem to "know" what t1.id is :(
Here follows my entire query, it goes to show table1 = _product_sku, table2 = _product_sku_data, t1 = ps, t2 = psd
SELECT ps.id, psd.description, psd.lang
FROM _product_sku ps
CROSS JOIN
( SELECT lang, title, description
FROM _product_sku_data
WHERE product_sku_id = ps.id
ORDER BY CASE WHEN lang='$this->profile_language_preference' THEN 0
WHEN lang='$this->browser_language' THEN 1
WHEN lang='default' THEN 2
ELSE 3
END
LIMIT 1
) AS psd
Edit:
This version uses variables to provide some sort of ranking within the available languages. Tables and test-data are not from the original question, but from the query OP provided as an answer.
It produced the expected results when I tried it:
SELECT id, description, lang
FROM
(
SELECT ps.id, psd.description, psd.lang,
CASE
WHEN #id != ps.id THEN #rownum := 1
ELSE #rownum := #rownum + 1
END AS rank,
#id := ps.id
FROM _product_sku ps
JOIN _product_sku_data psd ON ( psd.product_sku_id = ps.id )
JOIN ( SELECT #id:=NULL, #rownum:=0 ) x
ORDER BY id,
CASE WHEN lang='$this->profile_language_preference' THEN 0
WHEN lang='$this->browser_language' THEN 1
WHEN lang='default' THEN 2
ELSE 3
END
) x
WHERE rank = 1;
Old version which did not work, since ps.id is not known in the WHERE clause:
This one should return you the rows of table1 with the "best matching" row of table2 by using LIMIT 1 and ordering languages as defined:
SELECT t1.id, t2.lang, t2.some_column
FROM table1 t1
CROSS JOIN
( SELECT lang, some_column
FROM table2
WHERE table1_id = t1.id
ORDER BY CASE WHEN lang='fr' THEN 0
WHEN lang='eu' THEN 1
WHEN lang='default' THEN 2
ELSE 3
END
LIMIT 1
) t2
I've got a query joining several tables and returning quite a few columns.
An indexed column of another table references the PK of one of these joined tables. Now I would like to add another column to the query that states if at least one row with that ID exists in the new table.
So if I have one of the old tables
ID
1
2
3
and the new table
REF_ID
1
1
1
3
then I'd like to get
ID REF_EXISTS
1 1
2 0
3 1
I can think of several ways to do that, but what is the most elegant/efficient one?
EDIT
I tested the performance of the queries provided with 50.000 records in the old table, every other record matched by two rows in the new table, so half of the records have REF_EXISTS=1.
I'm adding average results as comments to the answers in case anyone is interested. Thanks everyone!
Another option:
select O.ID
, case when N.ref_id is not null then 1 else 0 end as ref_exists
from old_table o
left outer join (select distinct ref_id from new_table) N
on O.id = N.ref_id
I would:
select distinct ID,
case when exists (select 1 from REF_TABLE where ID_TABLE.ID = REF_TABLE.REF_ID)
then 1 else 0 end
from ID_TABLE
Provided you have indexes on the PK and FK you will get away with a table scan and index lookups.
Regards
K
Use:
SELECT DISTINCT t1.id,
CASE WHEN t2.ref_id IS NULL THEN 0 ELSE 1 END AS REF_EXISTS
FROM TABLE_1 t1
LEFT JOIN TABLE_2 t2 ON t2.ref_id = t1.id
Added DISTINCT to ensure only unique rows are displayed.
A join could return multiple rows for one id, as it does for id=1 in the example data. You can limit it to one row per id with a group by:
SELECT
t1.id
, COUNT(DISTINCT t2.ref_id) as REF_EXISTS
FROM TABLE_1 t1
LEFT JOIN TABLE_2 t2 ON t2.ref_id = t1.id
GROUP BY t1.id
The group by ensures there's only one row per id. And count(distinct t2.ref_id) will be 1 if a row is found and 0 otherwise.
EDIT: You can rewrite it without a group by, but I doubt that will make things easer:
SELECT
t1.id
, CASE WHEN EXISTS (
SELECT * FROM TABLE_2 t2 WHERE t2.ref_id = t1.id)
THEN 1 ELSE 0 END as REF_EXISTS
, ....
FROM TABLE_1 t1
I have a table where one column has duplicate records but other columns are distinct. so something like this
Code SubCode version status
1234 D1 1 A
1234 D1 0 P
1234 DA 1 A
1234 DB 1 P
5678 BB 1 A
5678 BB 0 P
5678 BP 1 A
5678 BJ 1 A
0987 HH 1 A
So in the above table. subcode and Version are unique values whereas Code is repeated. I want to transfer records from the above table into a temporary table. Only records I would like to transfer are where ALL the subcodes for a code have status of 'A' and I want them in the temp table only once.
So from example above. the temporary table should only have
5678 and 0987 since all the subcodes relative to 5678 have status of 'A' and all subcodes for 0987 (it only has one) have status of A. 1234 is ommited because its subcode 'DB' has status of 'P'
I'd appreciate any help!
Here's my solution
SELECT Code
FROM
(
SELECT
Code,
COUNT(SubCode) as SubCodeCount
SUM(CASE WHEN ACount > 0 THEN 1 ELSE 0 END)
as SubCodeCountWithA
FROM
(
SELECT
Code,
SubCode,
SUM(CASE WHEN Status = 'A' THEN 1 ELSE 0 END)
as ACount
FROM CodeTable
GROUP BY Code, SubCode
) sub
GROUP BY Code
) sub2
WHERE SubCodeCountWithA = SubCodeCount
Let's break it down from the inside out.
SELECT
Code,
SubCode,
SUM(CASE WHEN Status = 'A' THEN 1 ELSE 0 END)
as ACount
FROM CodeTable
GROUP BY Code, SubCode
Group up the codes and subcodes (Each row is a distinct pairing of Code and Subcode). See how many A's occured in each pairing.
SELECT
Code,
COUNT(SubCode) as SubCodeCount
SUM(CASE WHEN ACount > 0 THEN 1 ELSE 0 END)
as SubCodeCountWithA
FROM
--previous
GROUP BY Code
Regroup those pairings by Code (now each row is a Code) and count how many subcodes there are, and how many subcodes had an A.
SELECT Code
FROM
--previous
WHERE SubCodeCountWithA = SubCodeCount
Emit those codes with have the same number of subcodes as subcodes with A's.
It's a little unclear as to whether or not the version column comes into play. For example, do you only want to consider rows with the largest version or if ANY subcde has an "A" should it count. Take 5678, BB for example, where version 1 has an "A" and version 0 has a "B". Is 5678 included because at least one of subcode BB has an "A" or is it because version 1 has an "A".
The following code assumes that you want all codes where every subcode has at least one "A" regardless of the version.
SELECT
T1.code,
T1.subcode,
T1.version,
T1.status
FROM
MyTable T1
WHERE
(
SELECT COUNT(DISTINCT subcode)
FROM MyTable T2
WHERE T2.code = T1.code
) =
(
SELECT COUNT(DISTINCT subcode)
FROM MyTable T3
WHERE T3.code = T1.code AND T3.status = 'A'
)
Performance may be abysmal if your table is large. I'll try to come up with a query that is likely to have better performance since this was off the top of my head.
Also, if you explain the full extent of your problem maybe we can find a way to get rid of that temp table... ;)
Here are two more possible methods. Still a lot of subqueries, but they look like they will perform better than the method above. They are both very similar, although the second one here had a better query plan in my DB. Of course, with limited data and no indexing that's not a great test. You should try all of the methods out and see which is best for your database.
SELECT
T1.code,
T1.subcode,
T1.version,
T1.status
FROM
MyTable T1
WHERE
EXISTS
(
SELECT *
FROM MyTable T2
WHERE T2.code = T1.code
AND T2.status = 'A'
) AND
NOT EXISTS
(
SELECT *
FROM MyTable T3
LEFT OUTER JOIN MyTable T4 ON
T4.code = T3.code AND
T4.subcode = T3.subcode AND
T4.status = 'A'
WHERE T3.code = T1.code
AND T3.status <> 'A'
AND T4.code IS NULL
)
SELECT
T1.code,
T1.subcode,
T1.version,
T1.status
FROM
MyTable T1
WHERE
EXISTS
(
SELECT *
FROM MyTable T2
WHERE T2.code = T1.code
AND T2.status = 'A'
) AND
NOT EXISTS
(
SELECT *
FROM MyTable T3
WHERE T3.code = T1.code
AND T3.status <> 'A'
AND NOT EXISTS
(
SELECT *
FROM MyTable T4
WHERE T4.code = T3.code
AND T4.subcode = T3.subcode
AND T4.status = 'A'
)
)
In your select, add a where clause that reads:
Select [stuff]
From Table T
Where Exists
(Select * From Table
Where Code = T.Code
And Status = 'A')
And Not Exists
(Select * From Table I
Where Code = T.Code
And Not Exists
(Select * From Table
Where Code = I.Code
And SubCode = I.SubCode
And Status = 'A'))
In English,
Show me the rows,
where there is at least one row with status 'A',
and there are NO rows with any specific subcode,
that do not have at least one row with that code/subcode, with status 'A'
INSERT theTempTable (Code)
SELECT t.Code
FROM theTable t
LEFT OUTER JOIN theTable subT ON (t.Code = subT.Code AND subT.status <> 'A')
WHERE subT.Code IS NULL
GROUP BY t.Code
This should do the trick. The logic is a little tricky, but I'll do my best to explain how it is derived.
The outer join combined with the IS NULL check allows you to search for the absence of a criteria. Combine that with the inverse of what you're normally looking for (in this case status = 'A') and the query succeeds when there are no rows that do not match. This is the same as ((there are no rows) OR (all rows match)). Since we know that there are rows due to the other query on the table, all rows must match.