In a simplified scenario I have table T that looks somthing like:
Key Value
1 NULL
1 NULL
1 NULL
2 NULL
2 NULL
3 NULL
3 NULL
I also have a very time-consuming function Foo(Key) which must be considered as a black box (I must use it, I can't change it).
I want to update table T but in a more efficient way than
UPDATE T SET Value = dbo.Foo(Key)
Basically I would execute Foo only one time for each Key.
I tried something like
WITH Tmp1 AS
(
SELECT DISTINCT Key FROM T
)
, Tmp2 AS
(
SELECT Key, Foo(Key) Value FROM Tmp1
)
UPDATE T
SET T.Value = Tmp2.Value
FROM T JOIN Tmp2 ON T.Key = Tmp2.Key
but unexpectedly computing time doesn't change at all, because Sql Server seems to run Foo again on every row.
Any idea to solve this without other temporary tables?
One method is to use a temporary table. You don't have much control over how SQL Server decides to optimize its queries.
If you don't want a temporary table, you could do two updates:
with toupdate as (
select t.*, row_number() over (partition by id order by id) as seqnum
from t
)
update toupdate
set value = db.foo(key)
where seqnum = 1;
Then you can run a similar update again:
with toupdate as (
select t.*, max(value) over (partition by id) as as keyvalue
from t
)
update toupdate
set value = keyvalue
where value is null;
You might try it like this:
CREATE FUNCTION dbo.Foo(#TheKey INT)
RETURNS INT
AS
BEGIN
RETURN (SELECT #TheKey*2);
END
GO
CREATE TABLE #tbl(MyKey INT,MyValue INT);
INSERT INTO #tbl(MyKey) VALUES(1),(1),(1),(2),(2),(3),(3),(3);
SELECT * FROM #tbl;
DECLARE #tbl2 TABLE(MyKey INT,TheFooValue INT);
WITH DistinctKeys AS
(
SELECT DISTINCT MyKey FROM #tbl
)
INSERT INTO #tbl2
SELECT MyKey,dbo.Foo(MyKey) TheFooValue
FROM DistinctKeys;
UPDATE #tbl SET MyValue=TheFooValue
FROM #tbl
INNER JOIN #tbl2 AS tbl2 ON #tbl.MyKey=tbl2.MyKey;
SELECT * FROM #tbl2;
SELECT * FROM #tbl;
GO
DROP TABLE #tbl;
DROP FUNCTION dbo.Foo;
Related
I have following data:
DECLARE #temp TABLE (
ID int
,sn varchar(200)
,comment varchar(2000)
,rownumber int
)
insert into #temp values(1,'sn1',NULL,1)
insert into #temp values(2,'sn1','aaa',2)
insert into #temp values(3,'sn1','bbb',3)
insert into #temp values(4,'sn1',NULL,4)
insert into #temp values(5,'sn2',NULL,1)
insert into #temp values(6,'sn2',NULL,2)
insert into #temp values(7,'sn2',NULL,3)
select * from #temp
And I want to output like this:
2 sn1 aaa 2
5 sn2 NULL 1
same sn, if comment have value, get this lower rownumber's record. For sn1, have two records with comment value, so here, get the the record with rownumber=2
If comment doesn't have value, get the lower rownumber's record. For sn2, get the record with rownumber=1
May I know how to write this SQL?
This is a prioritization query. I think row_number() is the simplest method:
select t.*
from (select t.*,
row_number() over (partition by sn
order by (case when comment is not null then 1 else 2 end),
rownumber
) as seqnum
from #temp t
) t
where seqnum = 1;
Here is a db<>fiddle.
I want to achieve in MS SQL something like below, using 2 tables and through join instead of iteration.
From table A, I want each row to identify from table B which in the list is their nearest value, and when value has been selected, that value cannot re-used. Please help if you've done something like this before. Thank you in advance! #SOreadyToAsk
Below is a set-based solution using CTEs and windowing functions.
The ranked_matches CTE assigns a closest match rank for each row in TableA along with a closest match rank for each row in TableB, using the index value as a tie breaker.
The best_matches CTE returns rows from ranked_matches that have the best rank (rank value 1) for both rankings.
Finally, the outer query uses a LEFT JOIN from TableA to the to the best_matches CTE to include the TableA rows that were not assigned a best match due to the closes match being already assigned.
Note that this does not return a match for the index 3 TableA row indicated in your sample results. The closes match for this row is TableB index 3, a difference of 83. However, that TableB row is a closer match to the TableA index 2 row, a difference of 14 so it was already assigned. Please clarify you question if this isn't what you want. I think this technique can be tweaked accordingly.
CREATE TABLE dbo.TableA(
[index] int NOT NULL
CONSTRAINT PK_TableA PRIMARY KEY
, value int
);
CREATE TABLE dbo.TableB(
[index] int NOT NULL
CONSTRAINT PK_TableB PRIMARY KEY
, value int
);
INSERT INTO dbo.TableA
( [index], value )
VALUES ( 1, 123 ),
( 2, 245 ),
( 3, 342 ),
( 4, 456 ),
( 5, 608 );
INSERT INTO dbo.TableB
( [index], value )
VALUES ( 1, 152 ),
( 2, 159 ),
( 3, 259 );
WITH
ranked_matches AS (
SELECT
a.[index] AS a_index
, a.value AS a_value
, b.[index] b_index
, b.value AS b_value
, RANK() OVER(PARTITION BY a.[index] ORDER BY ABS(a.Value - b.value), b.[index]) AS a_match_rank
, RANK() OVER(PARTITION BY b.[index] ORDER BY ABS(a.Value - b.value), a.[index]) AS b_match_rank
FROM dbo.TableA AS a
CROSS JOIN dbo.TableB AS b
)
, best_matches AS (
SELECT
a_index
, a_value
, b_index
, b_value
FROM ranked_matches
WHERE
a_match_rank = 1
AND b_match_rank= 1
)
SELECT
TableA.[index] AS a_index
, TableA.value AS a_value
, best_matches.b_index
, best_matches.b_value
FROM dbo.TableA
LEFT JOIN best_matches ON
best_matches.a_index = TableA.[index]
ORDER BY
TableA.[index];
EDIT:
Although this method uses CTEs, recursion is not used and is therefore not limited to 32K recursions. There may be room for improvement here from a performance perspective, though.
I don't think it is possible without a cursor.
Even if it is possible to do it without a cursor, it would definitely require self-joins, maybe more than once. As a result performance is likely to be poor, likely worse than straight-forward cursor. And it is likely that it would be hard to understand the logic and later maintain this code. Sometimes cursors are useful.
The main difficulty is this part of the question:
when value has been selected, that value cannot re-used.
There was a similar question just few days ago.
The logic is straight-forward. Cursor loops through all rows of table A and with each iteration adds one row to the temporary destination table. To determine the value to add I use EXCEPT operator that takes all values from the table B and removes from them all values that have been used before. My solution assumes that there are no duplicates in value in table B. EXCEPT operator removes duplicates. If values in table B are not unique, then temporary table would hold unique indexB instead of valueB, but main logic remains the same.
Here is SQL Fiddle.
Sample data
DECLARE #TA TABLE (idx int, value int);
INSERT INTO #TA (idx, value) VALUES
(1, 123),
(2, 245),
(3, 342),
(4, 456),
(5, 608);
DECLARE #TB TABLE (idx int, value int);
INSERT INTO #TB (idx, value) VALUES
(1, 152),
(2, 159),
(3, 259);
Main query inserts result into temporary table #TDst. It is possible to write that INSERT without using explicit variable #CurrValueB, but it looks a bit cleaner with variable.
DECLARE #TDst TABLE (idx int, valueA int, valueB int);
DECLARE #CurrIdx int;
DECLARE #CurrValueA int;
DECLARE #CurrValueB int;
DECLARE #iFS int;
DECLARE #VarCursor CURSOR;
SET #VarCursor = CURSOR FAST_FORWARD
FOR
SELECT idx, value
FROM #TA
ORDER BY idx;
OPEN #VarCursor;
FETCH NEXT FROM #VarCursor INTO #CurrIdx, #CurrValueA;
SET #iFS = ##FETCH_STATUS;
WHILE #iFS = 0
BEGIN
SET #CurrValueB =
(
SELECT TOP(1) Diff.valueB
FROM
(
SELECT B.value AS valueB
FROM #TB AS B
EXCEPT -- remove values that have been selected before
SELECT Dst.valueB
FROM #TDst AS Dst
) AS Diff
ORDER BY ABS(Diff.valueB - #CurrValueA)
);
INSERT INTO #TDst (idx, valueA, valueB)
VALUES (#CurrIdx, #CurrValueA, #CurrValueB);
FETCH NEXT FROM #VarCursor INTO #CurrIdx, #CurrValueA;
SET #iFS = ##FETCH_STATUS;
END;
CLOSE #VarCursor;
DEALLOCATE #VarCursor;
SELECT * FROM #TDst ORDER BY idx;
Result
idx valueA valueB
1 123 152
2 245 259
3 342 159
4 456 NULL
5 608 NULL
It would help to have the following indexes:
TableA - (idx) include (value), because we SELECT idx, value ORDER BY idx;
TableB - (value) unique, Temp destination table - (valueB) unique filtered NOT NULL, to help EXCEPT. So, it may be better to have a temporary #table for result (or permanent table) instead of table variable, because table variables can't have indexes.
Another possible method would be to delete a row from table B (from original or from a copy) as its value is inserted into result. In this method we can avoid performing EXCEPT again and again and it could be faster overall, especially if it is OK to leave table B empty in the end. Still, I don't see how to avoid cursor and processing individual rows in sequence.
SQL Fiddle
DECLARE #TDst TABLE (idx int, valueA int, valueB int);
DECLARE #CurrIdx int;
DECLARE #CurrValueA int;
DECLARE #iFS int;
DECLARE #VarCursor CURSOR;
SET #VarCursor = CURSOR FAST_FORWARD
FOR
SELECT idx, value
FROM #TA
ORDER BY idx;
OPEN #VarCursor;
FETCH NEXT FROM #VarCursor INTO #CurrIdx, #CurrValueA;
SET #iFS = ##FETCH_STATUS;
WHILE #iFS = 0
BEGIN
WITH
CTE
AS
(
SELECT TOP(1) B.idx, B.value
FROM #TB AS B
ORDER BY ABS(B.value - #CurrValueA)
)
DELETE FROM CTE
OUTPUT #CurrIdx, #CurrValueA, deleted.value INTO #TDst;
FETCH NEXT FROM #VarCursor INTO #CurrIdx, #CurrValueA;
SET #iFS = ##FETCH_STATUS;
END;
CLOSE #VarCursor;
DEALLOCATE #VarCursor;
SELECT
A.idx
,A.value AS valueA
,Dst.valueB
FROM
#TA AS A
LEFT JOIN #TDst AS Dst ON Dst.idx = A.idx
ORDER BY idx;
I highly believe THIS IS NOT A GOOD PRACTICE because I am bypassing the policy SQL made for itself that functions with side-effects (INSERT,UPDATE,DELETE) is a NO, but due to the fact that I want solve this without resulting to iteration options, I came up with this and gave me better view of things now.
create table tablea
(
num INT,
val MONEY
)
create table tableb
(
num INT,
val MONEY
)
I created a hard-table temp which I shall drop from time-to-time.
if((select 1 from sys.tables where name = 'temp_tableb') is not null) begin drop table temp_tableb end
select * into temp_tableb from tableb
I created a function that executes xp_cmdshell (this is where the side-effect bypassing happens)
CREATE FUNCTION [dbo].[GetNearestMatch]
(
#ParamValue MONEY
)
RETURNS MONEY
AS
BEGIN
DECLARE #ReturnNum MONEY
, #ID INT
SELECT TOP 1
#ID = num
, #ReturnNum = val
FROM temp_tableb ORDER BY ABS(val - #ParamValue)
DECLARE #SQL varchar(500)
SELECT #SQL = 'osql -S' + ##servername + ' -E -q "delete from test..temp_tableb where num = ' + CONVERT(NVARCHAR(150),#ID) + ' "'
EXEC master..xp_cmdshell #SQL
RETURN #ReturnNum
END
and my usage in my query simply looks like this.
-- initialize temp
if((select 1 from sys.tables where name = 'temp_tableb') is not null) begin drop table temp_tableb end
select * into temp_tableb from tableb
-- query nearest match
select
*
, dbo.GetNearestMatch(a.val) AS [NearestValue]
from tablea a
and gave me this..
I want to copy records from one table to another. While doing this I want to set a flag of those records I copy.
This is how I would do it (simplified):
BEGIN TRANSACTION copyTran
insert into destination_table (name)
select top 100 name
from source_table WITH (TABLOCKX)
order by id
update source_table
set copy_flag = 1
where id in (select top 100 id from source_table order by id)
COMMIT TRANSACTION copyTran
Is there an easier way?
By leveraging OUTPUT clause you can boil it down to a single UPDATE statement
UPDATE source_table
SET copy_flag = 1
OUTPUT inserted.name
INTO destination_table(name)
WHERE id IN
(
SELECT TOP 100 id
FROM source_table
ORDER BY id
)
Note: Now tested. Should work just fine.
The problem with your query is, that you may get different records in your UPDATE if someone inserts some data while you are running your query. It is saver to use the INSERTED keyword.
Declare #temp TABLE (Id integer);
INSERT INTO destination_table (name)
OUTPUT INSERTED.Id into #temp
SELECT TOP 100 name
FROM source_table
ORDER BY id
UPDATE source_table
SET copy_flag = 1
WHERE Id IN (SELECT Id FROM #temp)
I think that you could use a temporary table in which you will store the top 100 ids from your source table, after having ordered them. This way you will avoid executing the select statement in where clause of update for each id.
BEGIN TRANSACTION copyTran
insert into destination_table (name)
select top 100 name
from source_table
order by id
declare #Ids TABLE(id int)
#Ids = (select top 100 id from source_table order by id)
update source_table
set copy_flag = 1
where id in (SELECT * FROM #Ids)
COMMIT TRANSACTION copyTran
I have like 10 diff temporary tables created in SQL server, what I am looking to do is union them all to a final temporary table holding them all on one table. All the tables have only one row and look pretty much exactly like the two temp tables below.
Here is what I have so far this is an example of just two of the temp tables as their all exactly like this one then #final is the table I want to union the all to:
create table #lo
(
mnbr bigint
)
insert into #login (mnbr)
select distinct (_ID)
FROM [KDB].[am_LOGS].[dbo].[_LOG]
WHERE time >= '2012-7-26 9:00:00
Select count(*) as countreject
from #lo
create table #pffblo
(
mber_br
)
insert into #pffblo (mber_br)
select distinct (mber_br)
from individ ip with (nolock)
join memb mp with (nolock)
on( ip.i_id=mp.i_id and mp.p_type=101)
where ip.times >= '2012-9-26 11:00:00.000'
select count(*) as countaccept
create table #final
(
countreject bigint
, Countacceptbigint
.....
)
insert into #final (Countreject, Countaccept....more rows here...)
select Countreject, Countaccept, ...more rows selected from temp tables.
from #final
union
(select * from #lo)
union
(select * from #pffblo)
select *
from #final
drop table #lo
drop table #pffblo
drop table #final
if this the form to union the rows form those temp tables to this final one. Then is this correct way to show all those rows that were thus unioned. When I do this union I get message number of columns in union need to match number of columns selected in union
I think you're using a union the wrong way. A union is used when you have to datasets that are the same structure and you want to put them into one dataset.
e.g.:
CREATE TABLE #Table1
(
col1 BIGINT
)
CREATE TABLE #Table2
(
col1 BIGINT
)
--populate the temporary tables
CREATE TABLE #Final
(
col1 BIGINT
)
INSERT INTO #Final (col1)
SELECT *
FROM #Table1
UNION
SELECT *
FROM #Table2
drop table #table1
drop table #table2
drop table #Final
I think what you're trying to do is get 1 data set with the count of all your tables in it. Union won't do this.
The easiest way (although not very performant) would be to do select statements like the following:
CREATE TABLE #Table1
(
col1 BIGINT
)
CREATE TABLE #Table2
(
col1 BIGINT
)
--populate the temporary tables
CREATE TABLE #Final
(
col1 BIGINT,
col2 BIGINT
)
INSERT INTO #Final (col1, col2)
select (SELECT Count(*) FROM #Table1) as a, (SELECT Count(*) FROM #Table2) as b
select * From #Final
drop table #table1
drop table #table2
drop table #Final
It appears that you want to take the values from each of temp tables and then place then into a single row of data. This is basically a PIVOT, you can use something like this:
create table #final
(
countreject bigint
, Countaccept bigint
.....
)
insert into #final (Countreject, Countaccept....more rows here...)
select
from
(
select count(*) value, 'Countreject' col -- your UNION ALL's here
from #lo
union all
select count(*) value, 'countaccept' col
from #pffblo
) x
pivot
(
max(value)
for col in ([Countreject], [countaccept])
) p
Explanation:
You will create a subquery similar to this that will contain the COUNT for each of your individual temp table. There are two columns in the subquery, one column contains the count(*) from the table and the other column is the name of the alias:
select count(*) value, 'Countreject' col
from #lo
union all
select count(*) value, 'countaccept' col
from #pffblo
You then PIVOT these values to insert into your final temp table.
If you do not want to use PIVOT, then you can use a CASE statement with an aggregate function:
insert into #final (Countreject, Countaccept....more rows here...)
select max(case when col = 'Countreject' then value end) Countreject,
max(case when col = 'countaccept' then value end) countaccept
from
(
select count(*) value, 'Countreject' col -- your UNION ALL's here
from #lo
union all
select count(*) value, 'countaccept' col
from #pffblo
) x
Or you might be able to JOIN all of the temp tables similar to this, where you create a row_number() for the one record in the table and then you join the tables with the row_number():
insert into #final (Countreject, Countaccept....more rows here...)
select isnull(lo.Countreject, 0) Countreject,
isnull(pffblo.Countaccept, 0) Countaccept
from
(
select count(*) Countreject,
row_number() over(order by (SELECT 0)) rn
from #lo
) lo
left join
(
select count(*) Countaccept,
row_number() over(order by (SELECT 0)) rn
from #pffblo
) pffblo
on lo.rn = pffblo.rn
SELECT *
INTO #1
FROM TABLE2
UNION
SELECT *
FROM TABLE3
UNION
SELECT *
FROM TABLE4
If you would like to get count for each temporary table in the resulting table, you will need just to calculate it for each column in subquery:
INSERT INTO result (col1, col2,...
SELECT
(SELECT COUNT() FROM tbl1) col1
,(SELECT COUNT() FROM tbl2) col2
..
Using SQL Server 2005
Table1
ID
Abc0012
BED0045
cAB0027
....
I want to replace all the ID values in the table1 like ABC0012, BED0045, CAB0027.
I want to make all characters as caps
Need Query Help
UPDATE Table1
SET ID = UPPER(ID)
Use the UPPER function
update table1 set id = upper(id)
Use upper:
SELECT upper(ID) FROM YourTable
or:
UPDATE YourTable SET ID=upper(ID)
If you want to change them:
UPDATE
Table1
SET
ID = UPPER(ID)
Could work, this is untested though.
I believe you should be able to do something like this:
UPDATE Table1 SET ID = UPPER(ID)
Here's a complete script that shows how to use the UPPER() function to achieve this:
declare #mytable table (
somevalue varchar (20)
)
insert into #mytable(
somevalue
)
values (
'abc123'
)
insert into #mytable(
somevalue
)
values (
'xYz456'
)
insert into #mytable(
somevalue
)
values (
'gjriwe345'
)
update #mytable
set somevalue = upper(somevalue)
select *
from #mytable