I have a table of students, a table of courses and a table containing a studentid and a courseid, I want to find all "student friends", meaning that they do at least two equal courses
WITH StudentsSubjects AS
(
SELECT 1 AS STUDENT_ID,'MATH' AS SUBJECTT
UNION ALL
SELECT 1,'ENGLISH'
UNION ALL
SELECT 1,'HISTORY'
UNION ALL
SELECT 1,'CS'
UNION ALL
SELECT 2,'HISTORY'
UNION ALL
SELECT 2,'GEO'
UNION ALL
SELECT 3,'CS'
UNION ALL
SELECT 3,'HISTORY'
)
SELECT X.PRIMARY_STUDENT,X.SECONDARY_STUDENT
FROM
(
SELECT S.STUDENT_ID AS PRIMARY_STUDENT,S.SUBJECTT,S2.STUDENT_ID AS SECONDARY_STUDENT,
ROW_NUMBER()OVER(PARTITION BY S.STUDENT_ID,S2.STUDENT_ID ORDER BY S.STUDENT_ID)D
FROM StudentsSubjects AS S
JOIN StudentsSubjects AS S2 ON S.STUDENT_ID<>S2.STUDENT_ID AND S.SUBJECTT=S2.SUBJECTT
)X WHERE X.D>1
ORDER BY X.PRIMARY_STUDENT
Common Table Expression StudentsSubjects is a substitute for your "a table containing a studentid and a courseid". Replace it with your actual table name
Related
I have two tables that I want to union together then perform some math functions on the combined table.
I know how to do the math for each separate table, but throwing in a union table to go off of is out of my league.
Here's the math for one table using column header "UnitsReceived" and "AsnPsUnits"
The other table would have headers: "cUnitsReceived" and "cAsnPsUnits"
select VendName,
1-abs(((cast(sum(UnitsReceived) as decimal(5,0))) - (cast(sum(AsnPsUnits) as decimal(5,0)))) /(cast(sum(AsnPsUnits) as decimal(5,0)))) as ASNpsAcc
from VenTest2
where ID<20
group by VendName
How would I perform this function after the union of two tables?
You'll need to get the unioned tables into some table object before performing your function. This could be done using:
A Common Table Expression
with cte as (
select ID, VALUE from A
union all
select ID, VALUE from B
)
select
*
,myfunction(VALUE) as MyFunctionResult
from
cte
A temp table
select ID, VALUE into #myTempTable from A
insert into #myTempTable select ID, VALUE from B
select
*
,myfunction(VALUE) as MyFunctionResult
from
#myTempTable
A table variable
declare #myTableVariable table (ID int, VALUE decimal)
insert into #myTableVariable
select ID, VALUE from A
union all
select ID, VALUE from B
select
*
,myfunction(VALUE) as MyFunctionResult
from
#myTableVariable
A sub query
select
*
,myfunction(VALUE) as MyFunctionResult
from
(
select ID, VALUE from A
union all
select ID, VALUE from B
) mySubQuery
This will help with the subq being the union
select VendName,
1-abs(((cast(sum(UnitsReceived) as decimal(5,0))) - (cast(sum(AsnPsUnits) as decimal(5,0)))) /(cast(sum(AsnPsUnits) as decimal(5,0)))) as ASNpsAcc
from
(
select ID, UnitsReceived, AsnPsUnits from VenTest2 where ID<20
union
select ID1, UnitsReceived1, AsnPsUnits1 from VenTest1
)a
group by VendName
This is not the way, brothers:
select VendName,
1-abs(((cast(sum(UnitsReceived) as decimal(10,2))) - (cast(sum(AsnPsUnits) as decimal(10,2)))) /(cast(sum(AsnPsUnits) as decimal(10,2)))) as ASNpsAcc
from VenTest2
where ID<10
group by VendName
union
select cVendName,
1-abs(((cast(sum(cUnitsReceived) as decimal(10,2))) - (cast(sum(casnpsunits) as decimal(10,2)))) /(cast(sum(cAsnPsUnits) as decimal(10,2)))) as ASNpsAcc
from CTest
where id <10
group by cvendname
I need the count of this:
select distinct ID
from (
select ID from A
union all
select ID from B
union all
select ID from C
) ids
GROUP BY ID HAVING COUNT(*) > 1;
but I have no idea how to do it.
Use a subquery:
select count(*)
from (select ID
from (select ID from A
union all
select ID from B
union all
select ID from C
) ids
group by ID
having count(*) > 1
) i;
SELECT DISTINCT is almost never needed with GROUP BY and definitely not in this case.
You just want to find the id that appear 2 more times in the A,B,C table, the SQL is below:
select count(1) from (
select
id,
count(1)
from
(
select ID from A
union all
select ID from B
union all
select ID from C
)
group by id having(count(1)>1)
) tmp
I want to select a third column based on two distant columns within the same table.
I could only think of this:
select tl.thirdcolumn
from table1 t1
WHERE
EXISTS
(
Select distinct tl.firstcolumn , t1.secondcolumn
From t1
)
This:
select distinct tl.thirdcolumn
from table t1
won't work as I don't want the distinct thirdrow. I want the thirdrow to be based on the first two rows being distinct.
I guess its a kind of nested sql statment with a select top 1... idk
CATEGORY NAME Query
---------------------------------------------------
STUDENTS NUMBER_OF_CHAPTERS QueryA
STUDENTS NUMBER_OF_STUDENT_MEMBERS QueryB
STUDENTS NUMBER_OF_STUDENT_MEMBERS QueryB
MEMBERS NUMBER_OF_MEMBERS_WORLDWIDE QueryC
MEMBERS NUMBER_OF_MEMBERS_WORLDWIDE QueryC
Your question is rather hard to follow, but I think you might simply want group by:
select tl.firstcolumn , t1.secondcolumn, max(tl.thirdcolumn)
from table1 t1
group by tl.firstcolumn , t1.secondcolumn;
If you want rows where the pair of values only appears once, then add having count(*) = 1:
select tl.firstcolumn , t1.secondcolumn, max(tl.thirdcolumn)
from table1 t1
group by tl.firstcolumn , t1.secondcolumn
having count(*) = 1;
Query -
SELECT
CATEGORY,NAME,QUERY
FROM
(
WITH TAB AS (
SELECT
'STUDENTS' AS CATEGORY,
'NUMBER_OF_CHAPTERS' AS NAME,
'QUERYA' AS QUERY
FROM
DUAL
UNION ALL
SELECT
'STUDENTS' AS CATEGORY,
'NUMBER_OF_STUDENT_MEMBERS' AS NAME,
'QUERYB' AS QUERY
FROM
DUAL
UNION ALL
SELECT
'STUDENTS' AS CATEGORY,
'NUMBER_OF_STUDENT_MEMBERS' AS NAME,
'QUERYB' AS QUERY
FROM
DUAL
UNION ALL
SELECT
'MEMBERS' AS CATEGORY,
'NUMBER_OF_MEMBERS_WORLDWIDE' AS NAME,
'QUERYC' AS QUERY
FROM
DUAL
UNION ALL
SELECT
'MEMBERS' AS CATEGORY,
'NUMBER_OF_MEMBERS_WORLDWIDE' AS NAME,
'QUERYC' AS QUERY
FROM
DUAL
) SELECT
CATEGORY,
NAME,
QUERY,
COUNT(*) OVER(PARTITION BY
CATEGORY,
NAME
ORDER BY
CATEGORY,
NAME,
QUERY
) AS RNK
FROM
TAB
)
WHERE
RNK = 1;
Output -
"CATEGORY","NAME","QUERY"
"STUDENTS","NUMBER_OF_CHAPTERS","QueryA"
Is there a way to union two tables, but keep the rows from the first table appearing first in the result set? However orderby column is not in select query
For example:
Table 1
name surname
-------------------
John Doe
Bob Marley
Ras Tafari
Table 2
name surname
------------------
Lucky Dube
Abby Arnold
Result
Expected Result:
name surname
-------------------
John Doe
Bob Marley
Ras Tafari
Lucky Dube
Abby Arnold
I am bringing Data by following query
SELECT name,surname FROM TABLE 1 ORDER BY ID
UNION
SELECT name,surname FROM TABLE 2
The above query is not keeping track of order by after union.
P.S - I dont want to show ID in my select query
I am getting ORDER BY Column by joining tables. Following is my real query
SELECT tbl_Event_Type_Sort_Orders.Appraisal_Event_Type_ID AS Appraisal_Event_Type_ID , ISNULL(tbl_Appraisal_Event_Types.Appraisal_Event_Type_Display_Name, 'UnCategorized') AS Appraisal_Event_Type_Display_Name
INTO #temptbl
FROM tbl_Event_Type_Sort_Orders
INNER JOIN tbl_Appraisal_Event_Types
ON tbl_Event_Type_Sort_Orders.Appraisal_Event_Type_ID = tbl_Appraisal_Event_Types.Appraisal_Event_Type_ID
WHERE 1=1
AND User_Name='abc'
ORDER BY tbl_Event_Type_Sort_Orders.Sort_Order
SELECT * FROM #temptbl
UNION
SELECT DISTINCT (tbl_Appraisal_Event_Types.Appraisal_Event_Type_ID) AS Appraisal_Event_Type_ID , ISNULL(tbl_Appraisal_Event_Types.Appraisal_Event_Type_Display_Name, 'UnCategorized') AS Appraisal_Event_Type_Display_Name
FROM tbl_Appraisal_Event_Types
INNER JOIN tbl_Appraisal_Events
ON tbl_Appraisal_Event_Types.Appraisal_Event_Type_ID = tbl_Appraisal_Events.Event_Type_ID
INNER JOIN tbl_Appraisals
ON tbl_Appraisal_Events.Appraisal_ID = tbl_Appraisal_Events.Appraisal_ID
WHERE 1=1
AND ((tbl_Appraisals.Assigned_To_Staff_User) = 'abc' OR (tbl_Appraisals.Assigned_To_Staff_User2) = 'abc' OR (tbl_Appraisals.Assigned_To_Staff_User3) = 'abc')
Put a UNION ALL in a derived table. To keep duplicate elimination, do select distinct and also add a NOT EXISTS to second select to avoid returning same person twice if found in both tables:
select name, surname
from
(
select distinct name, surname, 1 as tno
from table1
union all
select distinct name, surname, 2 as tno
from table2 t2
where not exists (select * from table1 t1
where t2.name = t1.name
and t2.surname = t1.surname)
) dt
order by tno, surname, name
You can use a column for the table and one for the ID to order by:
SELECT x.name, x.surname FROM (
SELECT ID, TableID = 1, name, surname
FROM table1
UNION ALL
SELECT ID = -1, TableID = 2, name, surname
FROM table2
) x
ORDER BY x.TableID, x.ID
You can write as below, if you are ok with duplicate data then please use UNION ALL it will be faster:
SELECT NAME, surname FROM (
SELECT ID,name,surname FROM TABLE 1
UNION
SELECT ID,name,surname FROM TABLE 2 ) t ORDER BY ID
this will order the first row sets first then by anything you need
(haven't tested the code)
;with cte_1
as
(SELECT ID,name,surname,1 as table_id FROM TABLE 1
UNION
SELECT ID,name,surname,2 as table_id FROM TABLE 2 )
SELECT name, surname
FROM cte_1
ORDER BY table_id,ID
simply use a UNION clause with out order by.
SELECT name,surname FROM TABLE 1
UNION
SELECT name,surname FROM TABLE 2
if you wanted to order first table use the below query.
;WITH cte_1
AS
(SELECT name,surname,ROW_NUMBER()OVER(ORDER BY Id)b FROM TABLE 1 )
SELECT name,surname
FROM cte_1
UNION
SELECT name,surname
FROM TABLE 2
I have following query, that's not working.
select * from table where id in (
1,2, (select id from another_table)
)
How i can rewrite it?
How about
select * from table
where id in (1,2)
or id in (select id from another_table)
Take care and use parentheses when adding additional WHERE-conditions using and!!!
select *
from table
where id in (1,2) OR id in(
select id from another_table
)
select * from table where id in (
select 1 as id from dual
union all
select 2 as id from dual
union all
select id from another_table
)
select * from table where id in (
select 1 from dual
union all
select 2 from dual
union all
select id from another_table);
I'm using union because this is faster than using an OR clause which also can be used.