i have my table:
ID | NAME | TYPE
1 | A | 1
2 | A | NULL
3 | B | NULL
4 | C | 2
5 | D | NULL
6 | D | NULL
and i want to for example if i choose Type 1 i get the row but i want all the null values from the other.
ID | NAME | TYPE
1 | A | 1
3 | B | NULL
5 | D | NULL
6 | D | NULL
sometime like this. i try with union but i get repeat A | NULL
thx for all
You seem to want:
select t.*
from t
where type = 1
union all
select t.*
from t
where type is null and
not exists (select 1 from t t2 where t2.name = t.name and t2.type = 1);
You don't actually need the union all:
select t.*
from t
where type = 1 or
(type is null and
not exists (select 1 from t t2 where t2.name = t.name and t2.type = 1)
);
Related
I have the table, where I need to take the next row after the row which has course 'TA' and flag = 1. For this I created the column rnum (OVER DATE) which may help for finding it
| student | date | course | flag | rnum |
| ------- | ----- | ----------- | ---- | ---- |
| 1 | 17:00 | Math | null | 1 |
| 1 | 17:10 | Python | null | 2 |
| 1 | 17:15 | TA | 1 | 3 |
| 1 | 17:20 | English | null | 4 |
| 1 | 17:35 | Geography | null | 5 |
| 2 | 16:10 | English | null | 1 |
| 2 | 16:20 | TA | 1 | 2 |
| 2 | 16:30 | SQL | null | 3 |
| 2 | 16:40 | Python | null | 4 |
| 3 | 19:05 | English | null | 1 |
| 3 | 19:20 | Literachure | null | 2 |
| 3 | 19:30 | TA | null | 3 |
| 3 | 19:40 | Python | null | 4 |
| 3 | 19:50 | Python | null | 5 |
As a result I should have:
| student | date | course | flag | rnum |
| ------- | ----- | ------- | ---- | ---- |
| 1 | 17:20 | English | null | 4 |
| 2 | 16:30 | SQL | null | 3 |
There are many ways to get your desired result, let's see some of them.
1) EXISTS
You can use the EXISTS clause, specifying a subquery to match for the condition.
SELECT T2.*
FROM #MyTable T2
WHERE EXISTS (
SELECT 'x' x
FROM #MyTable T1
WHERE T1.course = 'TA' AND T1.flag = 1
AND T1.student = T2.student AND T2.rnum = T1.rnum + 1
)
2) LAG
You ca use window function LAG to access previous row for a given order and then filter your resultset with your conditions.
SELECT w.student, w.date, w.course, w.flag, w.rnum
FROM (
SELECT T1.*
, LAG(course, 1) OVER (PARTITION BY student ORDER BY rnum) prevCourse
, LAG(flag, 1) OVER (PARTITION BY student ORDER BY rnum) prevFlag
FROM #MyTable T1
) w
WHERE prevCourse = 'TA' AND prevFlag = 1
3) JOIN
You can self-JOIN your table on the next rnum and keep only the rows who match the right condition.
SELECT T2.*
FROM MyTable T1
JOIN MyTable T2 ON T1.student = T2.student AND T2.rnum = T1.rnum + 1
WHERE T1.course = 'TA' AND T1.flag = 1
4) CROSS APPLY
You can use CROSS APPLY to specify a subquery with the matching condition. It is pretty similar to EXISTS clause, but you will also get in your resultset the columns from the subquery.
SELECT T2.*
FROM #MyTable T2
CROSS APPLY (
SELECT 'x' x
FROM #MyTable T1
WHERE T1.course = 'TA' AND T1.flag = 1
AND T1.student = T2.student AND T2.rnum = T1.rnum + 1
) x
5) CTE
You can use common table expression (CTE) to extract matching rows and then use it to filter your table with a JOIN.
;WITH
T1 AS (
SELECT student, rnum
FROM #MyTable T1
WHERE T1.course = 'TA' AND T1.flag = 1
)
SELECT T2.*
FROM #MyTable T2
JOIN T1 ON T1.student = T2.student AND T2.rnum = T1.rnum + 1
Adding the rownumber was a good start, you can use it to join the table with itself:
WITH matches AS (
SELECT
student,
rnum
FROM table
WHERE flag = 1
AND course = 'TA'
)
SELECT t.*
FROM table t
JOIN matches m
on t.student = m.student
and t.rnum = m.rnum + 1
I have a problem with grouping data in postgresql. let say that I have table called my_table
some_id | description | other_id
---------|-----------------|-----------
1 | description-1 | a
1 | description-2 | b
2 | description-3 | a
2 | description-4 | a
3 | description-5 | a
3 | description-6 | b
3 | description-7 | b
4 | description-8 | a
4 | description-9 | a
4 | description-10 | a
...
I would like to group my database based on some_id then differentiate which one has same and different other_id
I would expecting 2 type of queries: 1 that has same other_id and 1 that has different other_id
Expected result
some_id | description | other_id
---------|-----------------|-----------
2 | description-3 | a
2 | description-4 | a
4 | description-8 | a
4 | description-9 | a
4 | description-10 | a
AND
some_id | description | other_id
---------|-----------------|-----------
1 | description-1 | a
1 | description-2 | b
3 | description-5 | a
3 | description-6 | b
3 | description-7 | b
I am open for suggestion both using sequelize or raw query
thank you
One approach, using MIN and MAX as analytic functions:
WITH cte AS (
SELECT *, MIN(other_id) OVER (PARTITION BY some_id) min_other_id,
MAX(other_id) OVER (PARTITION BY some_id) max_other_id
FROM yourTable
)
-- all some_id the same
SELECT some_id, description, other_id
FROM cte
WHERE min_other_id = max_other_id;
-- not all some_id the same
SELECT some_id, description, other_id
FROM cte
WHERE min_other_id <> max_other_id;
Demo
You can also do this using exists and not exists:
-- all same
select t.*
from my_table t
where not exists (select 1
from my_table t2
where t2.some_id = t.some_id and t2.other_id <> t.other_id
);
-- any different
select t.*
from my_table t
where exists (select 1
from my_table t2
where t2.some_id = t.some_id and t2.other_id <> t.other_id
);
Note that this ignores NULL values. If you want them treated as a "different" value then use is distinct from rather than <>.
I want to select rows in sql server, there's my questions below:
Table1
--------------------------
| Name | Type |
--------------------------
| A | 1 |
| A | 2 |
| B | 1 |
| B | 3 |
| A | 3 |
| C | 1 |
| C | 3 |
| D | 1 |
| D | 2 |
| D | 3 |
| . | . |
| . | . |
Select rows like below:
Table2
--------------------------
| Name | Type |
--------------------------
| A | 1 |
| A | 2 |
| A | 3 |
| D | 1 |
| D | 2 |
| D | 3 |
| . | . |
| . | . |
The select rules is...
Show Name and Type which Type must have 1,2 and 3.
Example: A had 1,2,3 types,so i would select it.
Example: B only has 1,2 types,so i wouldn't select it.
You can use window functions for this:
select name, type
from (
select
t.*,
sum(case when type in (1, 2, 3) then 1 else 0 end)
over(partition by name) cnt
from mytable t
) t
where cnt = 3
This assumes that each (name, type) tuple occurs only once in the original table, which is consistant with your sample data.
Demo on DB Fiddle:
name | type
:--- | ---:
A | 1
A | 2
A | 3
D | 1
D | 2
D | 3
You could use INNER JOINs on the three Type columns to achieve this:
SELECT Table1.[Name],
Table1.[Type]
FROM Table1
INNER JOIN (
SELECT [Name]
FROM Table1
WHERE ([Type] = 1)
) A ON A.[Name] = Table1.[Name]
INNER JOIN (
SELECT [Name]
FROM Table1
WHERE ([Type] = 2)
) B ON B.[Name] = A.[Name]
INNER JOIN (
SELECT [Name]
FROM Table1
WHERE ([Type] = 3)
) C ON C.[Name] = A.[Name]
This outputs:
Name Type
A 1
A 2
A 3
D 1
D 2
D 3
The matching sqlfiddle.
This works by returning rows that contain [Type] = 1, and then ONLY matching rows where [Type] = 2 and [Type] = 3. Then this is joined back to your main table and the results are returned.
Get the names with group by name and set the condition in the having clause:
select * from Table1
where name in (
select name
from Table1
group by name
having count(distinct type) = 3
)
If there are for the column Type other values than 1, 2, 3 then:
select * from Table1
where type in (1, 2, 3) and name in (
select name
from Table1
where type in (1, 2, 3)
group by name
having count(distinct type) = 3
)
See the demo.
Results:
> Name | Type
> :--- | ---:
> A | 1
> A | 2
> A | 3
> D | 1
> D | 2
> D | 3
you can use string_agg if it is sql server 2017 and above or Azure SQL as below:
Select * from #yourTable yt join (
select [name], string_agg([Type], ',') as st_types
from #YourTable
group by [name] ) a
on yt.name = a.[name] and a.st_types like '%1,2,3%'
I give you this, this will work if you have:
A 1
A 2
A 3
A 2
It will then only give you B.
SELECT *
FROM Table1
WHERE Name in (
SELECT Name from
(
SELECT Name, Type, count(Name) c from Table1 where Type = 1
GROUP BY Name, Type
HAVING count(Name) = 1
UNION
SELECT Name, Type, count(Name) c from Table1 where Type = 2
GROUP by Name, Type
HAVING count(Name) = 1
UNION
SELECT Name, Type, count(Name) c from Table1 where Type = 3
GROUP by Name, Type
HAVING count(Name) = 1) t
GROUP by name
HAVING count(c) = 3)
Here is the DEMO
I am looking to do a full outer join in order to get the following results. Mainly I am joining table 1 to table 2.
However in table 1, anything that has a 0 in Column A but has the same available value in Key 1 column (ABC100 Key 1 value in table 1), only use that record (record 1 in table 1), and ignore 0 record (record 2 in table 1)
When joined to table 2, specifically for ABC100, I am expecting to see output lines 1 and 2 in the expected table results.
Any help or ideas going about this?
Example:
Table 1
| Key 1 | Column A |
| ABC100 | 100 |
| ABC100 | 0 |
| ABC300 | 200 |
| ABC400 | 300 |
Table 2
| Key 2 | Column C |
| ABC100 | 100 |
| ABC200 | 50 |
| ABC300 | 200 |
Expected results:
| Key 1 | Column A | Key 2 | Column B | NVL(A,0) - NVL(B,0)
| ABC100 | 100 | ABC100 | 100 | 0
| ABC100 | NULL | NULL | NULL | NULL
| NULL | NULL | ABC200 | 50 | -50
| ABC300 | 200 | ABC300 | 200 | 0
| ABC400 | 300 | NULL | NULL | 300
Your result set suggests that you want something like this:
SELECT t1.key1,
(CASE WHEN t1.a <> 0 THEN t1.a END) as a,
(CASE WHEN t1.a <> 0 THEN t2.key2 END) as key2,
(CASE WHEN t1.a <> 0 THEN t2.c END) as ,
(CASE WHEN t1.a <> 0 THEN COALESCE(t1.A, 0) - COALESCE(t2.B, 0) END) as diff
FROM t1 FULL JOIN
t2
ON t1.Key1 = t2.Key2;
Your description suggests that you want:
SELECT t1.key1, t1.a, t2.key2, t2.c,
COALESCE(t1.A, 0) - COALESCE(t2.B, 0) as diff
FROM (SELECT t1.*
FROM
WHERE t1.A <> 0 OR
NOT EXISTS (SELECT 1 FROM t1 tt1 WHERE tt1.key1 = t1.key1 AND tt1.key1 <> 0)
) t1 FULL JOIN
t2
ON t1.Key1 = t2.Key2;
You could use:
SELECT t1.*, t2.*, NVL(t1.A,0) - NVL(t2.B,0)
FROM tab1 t1
FULL JOIN tab2 t2
ON t1.Key1=t2.Key2
i have 2 tables suppose table_1 & table_2
table_1 has 56 columns and 1.2 million records
my query is like
table_1 like
RollNumber | Subject | G | Part | Status
------------------------------------------------
1 | 1 | 1 | 1 | 1
1 | 1 | 1 | 2 | 1
1 | 2 | 1 | 1 | 1
1 | 2 | 1 | 2 | 5
1 | 3 | 1 | 1 | 0
1 | 3 | 1 | 2 | 1
2 | 1 | 2 | 1 | 1
2 | 1 | 2 | 2 | 1
2 | 2 | 2 | 1 | 1
2 | 2 | 2 | 2 | 1
2 | 3 | 2 | 1 | 1
2 | 3 | 2 | 2 | 1
3 | 1 | 2 | 1 | 1
3 | 1 | 2 | 2 | 1
3 | 2 | 2 | 1 | 1
3 | 2 | 2 | 2 | 1
3 | 3 | 2 | 1 | 0
3 | 3 | 2 | 2 | 1
i want all RollNumber (group by with 2nd and third column) from table_1 where any status is 0 but don't want students who also have status = 5(or other than 1)
i have tried this
select * from table_1 as t1
inner join table_2 as t2
on t1.column2 = t2.column2 and t1.column3 = t2.column3 and t1.column4 = t2.column4
where t1.column1 not in
(select column1 from table_1 where status = 5)
This is the inner most query of my qhole query
i have also tried EXCEPT clause
Both queries take too long to execute
Starting with SQL Server 2008 you can use count() over() to count how many total rows in a given group have a certain value.
In this case you'll want to count the number of status <> 1 per group and to only select rows that belong to a group with a count of 0.
select * from (
select * ,
count(case when status <> 1 then 1 end) over(partition by RollNumber, G) c
from table_1
) t where c = 0
You can use EXISTS in place of NOT IN. This will be faster as there will be a boolean comparison instead of string comparison.
select * from table_1 as t1
inner join table_2 as t2
on t1.column1 = t2.column1 and t1.column2 = t2.column2 and t1.column3 = t2.column3
where not EXISTS
(select 1 from table_1 where status = 5 and t1.column3 = table_1.column3)
Try to use NOT EXISTS instead of NOT IN
SELECT *
FROM table_1 AS t1
INNER JOIN table_2 AS t2
ON t1.column1 = t2.column1 AND t1.column2 = t2.column2 AND t1.column3 = t2.column3
WHERE NOT EXISTS(
SELECT 1
FROM table_1
WHERE status=5 AND column3=t1.column3
)