Please consider this table:
id Col1 Col2
--------------------------
1 nima null
18 john null
25 sara null
I have a select that retutn this records:
id Col
---------------
1 LA
2 WA
3 FL
I want to update this record on above table with same order that you see.for example update LA for nima and...
How I can do this?
thanks
You can update based on row_number() and the fact that you can update common table expressions in SQL Server, like this:
with cte1 as (
select Col2, row_number() over(order by id) as rn
from Table1
), cte2 as (
select col, row_number() over(order by id) as rn
from Table2
)
update c1 set
Col2 = c2.col
from cte1 as c1
left outer join cte2 as c2 on c2.rn = c1.rn
sql fiddle demo
Note that if your tables are large, the performance could be not very good. If this is the case, you can think about creating temporary tables with row_number columns and make this columns primary key of just create appropriate indexes
Related
I want to join two tables and remove duplicates from both the tables but keeping any duplicate value found in the first table.
T1
Name
-----
A
A
B
C
T2
Name
----
A
D
E
Expected result
A - > FROM T1
A - > FROM T1
B
C
D
E
I tried union but removes all duplicates of 'A' from both tables.
How can I achieve this?
Filter T2 before UNION ALL
select col
from T1
union all
select col
from T2
where not exists (select 1 from T1 where T1.col = T2.col)
Assuming you want the number of duplicates from the table with the most repetitions for each value, you can do it with the ROW_NUMBER() windowing function, to eliminate duplicates by their sequence with the set of repetitions in each table.
SELECT Name FROM (
SELECT Name, ROW_NUMBER() OVER ( PARTITION BY Name ORDER BY Name ) AS Row
FROM T1
UNION
SELECT Name, ROW_NUMBER() OVER ( PARTITION BY Name ORDER BY Name ) AS Row
FROM T2
) x
ORDER BY Name
To see how this works out, we add two B rows to T2 then do this:
SELECT Name, ROW_NUMBER() OVER ( PARTITION BY Name ORDER BY Name ) AS Row
FROM T1
Name Row
A 1
A 2
B 1
C 1
SELECT Name, ROW_NUMBER() OVER ( PARTITION BY Name ORDER BY Name ) AS Row
FROM T2
Name Row
A 1
B 1
B 2
D 1
E 1
Now UNION them without ALL to combine and eliminate duplicates:
SELECT Name, ROW_NUMBER() OVER ( PARTITION BY Name ORDER BY Name ) AS Row
FROM T1
UNION
SELECT Name, ROW_NUMBER() OVER ( PARTITION BY Name ORDER BY Name ) AS Row
FROM T2
Name Row
A 1
A 2
B 1
B 2
C 1
D 1
E 1
The final query up top is then just eliminating the Row column and sorting the result, to ensure ascending order.
See SQL Fiddle for demo.
select * from T1
union all
select * from T2 where name not in (select distinct name from T1)
Sql Fiddle Demo
you should use "union all" instead of "union".
"union" remove other duplicated records while "union all" gives all of them.
for you result,because of we filtered intersects from table 2 in "where",we don't need "UNION ALL"
select col1 from t1
union
select col1 from t2 where t2.col1 not in(select t1.col1 from t1)
I D'not know the following code is good practice or not But it's working
select name from T1
UNION
select name from T2 Where name not in (select name from T1)
The Above Query Filter the value based on T1 value and then join two tables values and show the result.
I hope it's helps you thanks.
Note : It's not better way to get result it's affect your performance.
I sure i update the better solution after my research
You want all names from T1 and all names from T2 except the names that are in T1.
So you can use UNION ALL for the 2 cases and the operator EXCEPT to filter the rows of T2:
SELECT Name FROM T1
UNION ALL
(
SELECT Name FROM T2
EXCEPT
SELECT Name FROM T1
)
See the demo.
Results:
> | Name |
> | :--- |
> | A |
> | A |
> | B |
> | C |
> | D |
> | E |
I want to select data with oracle join where rows with same ids will have data in a single row with multiple columns i.e
Table 1 :
ID DATA
1 test1
2 test2
3 test3
4 test4
Table 2 :
ID DATA
1 data1
1 data2
2 data3
2 data4
My Sql is like :
select * from table1 t1 inner join table2 t2
on t1.id = t2.id
output should be like :
ID value1 value2
1 data1 data2
2 data3 data4
If only 2 data per ID you could use a analytic to assign a row number for each ID and use conditional logic and aggregation to pivot the data manually...
I use a common table expression (CTE) to generate a row number so we can use it to specify the order in which the data is put in the columns for an ID.
WITH CTE AS (
SELECT ID, Data, row_number() over (partition by ID order by data) RN
FROM table1)
SELECT ID
, max(case when RN = 1 then data end) as Value1
, max(case when RN = 2 then data end) as Value2
FROM CTE
GROUP BY ID
Or you could use pivot statement itself.
WITH CTE AS (
SELECT ID, Data, row_number() over (partition by ID order by data) RN
FROM table1)
SELECT *
FROM (SELECT data, RN
FROM CTE t)
PIVOT (max(data)
for RN in (1,2))
ORDER BY ID
If however you have a dynamic number of data elements per ID then you have to write dynamic pivot. Several examples already exist on stack for this.
I have a table in SQL Server, and I need to sum a column, like the example below:
CREATE TABLE B
(
ID int,
Qty int,
)
INSERT INTO B VALUES (1,2)
INSERT INTO B VALUES (2,7)
INSERT INTO B VALUES (3,2)
INSERT INTO B VALUES (4,11)
SELECT *, '' AS TotalQty FROM B
ORDER BY ID
In this example what I need is the column TotalQty give me the values like:
2
9
11
22
How can it be achieved?
You can use SUM in a co-related subquery or CROSS APPLY like this
Co-related Subquery
SELECT ID,(SELECT SUM(Qty) FROM B WHERE B.id <= C.id) FROM B as C
ORDER BY ID
Using CROSS APPLY
SELECT ID,D.Qty FROM B as C
CROSS APPLY
(
SELECT SUM(Qty) Qty
FROM B WHERE B.id <= C.id
)AS D
ORDER BY ID
Output
1 2
2 9
3 11
4 22
If you were using SQL Server 2012 or above, SUM() with Over() clause could have been used like this.
SELECT ID, SUM(Qty) OVER(ORDER BY ID ASC) FROM B as C
ORDER BY ID
Edit
Another way to do this in SQL Server 2008 is using Recursive CTE. Something like this.
Note: This method is based on the answer by Roman Pekar on this thread Calculate a Running Total in SQL Server. Based on his observation this would perform better than co related subquery and CROSS APPLY both
;WITH CTE as
(
SELECT ID,Qty,ROW_NUMBER()OVER(ORDER BY ID ASC) as rn
FROM B
), CTE_Running_Total as
(
SELECT Id,rn,Qty,Qty as Running_Total
FROM CTE
WHERE rn = 1
UNION ALL
SELECT C1.Id,C1.rn,C1.Qty,C1.Qty + C2.Running_Total as Running_Total
FROM CTE C1
INNER JOIN CTE_Running_Total C2
ON C1.rn = C2.rn + 1
)
SELECT *
FROM CTE_Running_Total
ORDER BY Id
OPTION (maxrecursion 0)
What I am trying to accomplish:
Dataset 1
Name1
Name2
Name3
Dataset 2
Number1
Number2
Number3
will become 2 columns:
dataset1 dataset2
Name1 Number1
Name2 Number2
Name3 Number3
My datasets 1 & 2 will always have equal rows.
Which name linked to which number I don't care as long as two names are not linked to the same number and vice versa.
How can I solve this with SQL / SQL Server ?
If you don't want to add an identity column to the tables, you can use the ROW_NUMBER() function like this:
SELECT
T1.Col1,
T2.Col1
FROM
(SELECT Col1, ROW_NUMBER() OVER (ORDER BY Col1) AS N FROM Table1) T1
INNER JOIN
(SELECT Col1, ROW_NUMBER() OVER (ORDER BY Col1) AS N FROM Table2) T2
ON T1.N = T2.N
Here, replace Table1 and Table2 with the name of your tables, and replace Col1 with the name of the column (or columns) that you want to output from the two tables.
Add identity columns to both the tables and perform join on basis of these column
ALTER TABLE Table1
ADD ID INT IDENTITY(1,1) NOT NULL
ALTER TABLE Table2
ADD ID INT IDENTITY(1,1) NOT NULL
SELECT Table1.dataset1col , Table2.dataset2Col
From Table1 INNER JOIN Table2
ON Table1.ID = Table2.ID
This may work for you :
;WITH cte1 (name, rn)
AS (SELECT Name,
row_number()
OVER(
ORDER BY Name) rn
FROM Dataset1),
cte2 (Number, rn)
AS (SELECT Number,
row_number()
OVER(
ORDER BY Number) rn
FROM Dataset2)
SELECT name,
Number
FROM cte1
JOIN cte2
ON cte1.rn = cte2.rn
WITH Table1 AS
(
SELECT ROW_NUMBER() OVER (PARTITION BY ID ORDER BY Dataset1) as Rnk,Dataset1
FROM TA1
)
With Table2 AS
(
SELECT ROW_NUMBER() OVER (PARTITION BY ID ORDER BY Dataset2) as Rnk, Dataset2
FROM TA2
)
Select Table.Dataset1 as 'DataSet1', Table2.DataSet2 as 'DataSet2'
From Table1
inner join Table2 on Table1.Rnk = Table2.Rnk
Because you haven't added table name so I considered it as TA1 and TA2.
Another way of writing the query is:
select row_number() over (order by Names asc) as rownum,
Names
into #Temp1
from NameTable
select row_number() over (order by Numbers asc) as rownum,
Numbers
into #Temp2
from NumberTable
select Names, Numbers
from #Temp1
inner join #Temp2 on #Temp1.rownum = #Temp2.rownum
Demo
There are 3 possible solutions to this.
First: Use following trick (Warning: Use this in case of small datasets)
SELECT DISTINCT tbl1.col1, tbl2.col2
FROM
(SELECT FirstName AS col1, ROW_NUMBER() OVER (ORDER BY FirstName) Number FROM dbo.User) tbl1
INNER JOIN
(SELECT LastName AS col2, ROW_NUMBER() OVER (ORDER BY LastName) Number FROM dbo.User) tbl2
ON tbl1.Number = tbl2.Number
Second: Use variable tables to store result temporarily. This solution is for relatively large datasets. (approx records to 100s)
Third:
Use identitfy field in both tables as already mentioned by mmhasannn. But i will prefer this method least, as we need to modify our DB structure.
RECOMMENDED: Use variable tables approach
I'm using Microsoft's SQL Server 2008. I need to aggregate by a foreign key to randomly get a single value, but I'm stumped. Consider the following table:
id fk val
----------- ----------- ----
1 100 abc
2 101 def
3 102 ghi
4 102 jkl
The desired result would be:
fk val
----------- ----
100 abc
101 def
102 ghi
Where the val for fk 102 would randomly be either "ghi" or "jkl".
I tried using NEWID() to get unique random values, however, the JOIN fails since the NEWID() value is different depending on the sub query.
WITH withTable AS (
SELECT id, fk, val, CAST(NEWID() AS CHAR(36)) random
FROM exampleTable
)
SELECT t1.fk, t1.val
FROM withTable t1
JOIN (
SELECT fk, MAX(random) random
FROM withTable
GROUP BY fk
) t2 ON t2.random = t1.random
;
I'm stumped. Any ideas would be greatly appreciated.
I might think about it a little differently, using a special ranking function called ROW_NUMBER().
You basically apply a number to each row, grouped by fk, starting with 1, ordered randomly by using the NEWID() function as a sort value. From this you can select all rows where the row number was 1. The effect of this technique is that it randomizes which row gets assigned the value 1.
WITH withTable(id, fk, val, rownum) AS
(
SELECT
id, fk, val, ROW_NUMBER() OVER (PARTITION BY fk ORDER BY NEWID())
FROM
exampleTable
)
SELECT
*
FROM
withTable
WHERE
rownum = 1
This approach has the added benefit in that it takes care of the grouping and the randomization in one pass.
You can do this not with aggregation but with row_number():
select id, fk, val
from (select t1.*,
row_number() over (partition by fk order by newid()) as seqnum
from withTable t1
) t1
where seqnum = 1
One option is to get the values that are the same fk into a temp table then SELECT TOP 1 ORDER by NEWID()
That should work for you.