I have an immense doubt, is it possible to create a column calculated using two tables?
Table 1:
---------------------
id | Value1 |
---------------------
1 | 25 |
Table 2
---------------------
id | Value2 |
---------------------
1 | 5 |
Now, in a 3rd table I want a calculated column of the values 1 and 2?? is it possible?
Table 3
---------------------
id | Sumvalues |
---------------------
1 | ? |
or is there another method that can be used for "sumvalues" to self-adjust with the change of the other fields related to it?
The best option is to create a view in my opinion:
create view vMyView as
select T1.id,
T1.Value1 + T2.Value2
from [Table1] T1 join [Table2] T2 on T1.id = T2.id
This way, everytime you execute query against the view, you will get most actual data.
Use for adding value1 to value2:
SET #value1 = SELECT value1 FROM TABLE1;
SET #value2 = SELECT value2 FROM TABLE2;
SET #value3 = #value1+#value2;
INSERT INTO TABLE3 (value3) VALUES (#value3);
This may contain typos since I’m writting from a cell phone.
Related
Environment: SQL Server 2016; abstracted example of "real" data.
From a first query to a table containing XML data I have a SQL result set that has the following columns:
ID (int)
Names (XML)
Times (XML)
Values (XML)
Columns 2-4 contain multiple values in XML format, e.g.
Names:
Row 1: <name>TestR1</name><name>TestR2</name>...
Row 2: <name>TestS1</name><name>TestS2</name>...
Times:
Row 1: <time>0.1</time><time>0.2</time>...
Row 2: <time>-0.1</time><time>-0.2</time>...
Values:
Row 1: <value>1.1</value><value>1.2</value>...
Row 2: <value>-1.1</value><value>-1.2</value>...
The XML of all XML columns contain the exact same number of elements.
What I want now is to create a select that has the following output:
| ID | Name | Time | Value |
+----+--------+------+-------+
| 1 | TestR1 | 0.1 | 1.1 |
| 1 | TestR1 | 0.2 | 1.2 |
| .. | ...... | .... | ..... |
| 2 | TestS1 | -0.1 | -1.1 |
| 2 | TestS2 | -0.2 | -1.2 |
| .. | ...... | .... | ..... |
For a single column CROSS APPLY works fine:
SELECT ID, N.value('.', 'nvarchar(50)') AS ExtractedName
FROM <source>
CROSS APPLY <source>.nodes('/name') AS T(N)
Applying multiple CROSS APPLY statements makes no sense here to me.
I would guess it would work if I would create selects for each column that then produce individual result sets and perform a select over all of the result sets
but that's very likely not the best solution as I am duplicating selects for each additional column.
Any suggestions on how to design a query like that would be highly appreciated!
I'd suggest this approach:
First I create a declared table variable and fill it with your sample data to simulate your issue. This is called "MCVE", please try to provide this yourself in your next question.
DECLARE #tbl TABLE(ID INT, Names XML,Times XML,[Values] XML);
INSERT INTO #tbl VALUES
(1,'<name>TestR1</name><name>TestR2</name>','<time>0.1</time><time>0.2</time>','<value>1.1</value><value>1.2</value>')
,(2,'<name>TestS1</name><name>TestS2</name>','<time>0.3</time><time>0.4</time>','<value>2.1</value><value>2.2</value>');
--The query
SELECT t.ID
,t.Names.value('(/name[sql:column("tally.Nmbr")])[1]','nvarchar(max)') AS [Name]
,t.Times.value('(/time[sql:column("tally.Nmbr")])[1]','decimal(10,4)') AS [Time]
,t.[Values].value('(/value[sql:column("tally.Nmbr")])[1]','decimal(10,4)') AS [Value]
FROM #tbl t
CROSS APPLY
(
SELECT TOP(t.Names.value('count(*)','int')) ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) Nmbr FROM master..spt_values
) tally;
The idea in short:
We create a tally on the fly by using APPLY to create a list of numbers.
The TOP-clause will limit this list to the count of <name> elements in the given row.
In this case I take master..spt_values as a source for many rows. We do not need the content, just an appropriate list to create a tally. This said, if there is a physical numbers table in your database, this was even better.
Finally we can pick the content by the element's position using sql:column() to introduce the tally's value into the XQuery predicate.
I'm trying to add values in a junction table of a many to many relationship.
Tables look like these (all IDs are integers):
Table A
+------+----------+
| id_A | ext_id_A |
+------+----------+
| 1 | 100 |
| 2 | 101 |
| 3 | 102 |
+------+----------+
Table B is conceptually similar
+------+----------+
| id_B | ext_id_B |
+------+----------+
| 1 | 200 |
| 2 | 201 |
| 3 | 202 |
+------+----------+
Tables PK are id_A and id_B, as columns in my junction table are FK to those columns, but I have to insert values having only external ids (ext_id_A, ext_id_B).
External IDs are unique columns, (and therefore in a 1:1 with table id itself), so having ext_id I can lookup the exact row and get the id need to insert into junction table.
This is an example of what I've done so far, but doesn't look like an optimized sql statement:
-- Example table I receive with test values
declare #temp as table (
ext_id_a int not null,
ext_id_b int not null
);
insert into #temp values (100, 200), (101, 200), (101, 201);
--Insertion - code from my sp
declare #final as table (
id_a int not null,
id_b int not null
);
insert into #final
select a.id_a, b.id_b
from #temp as t
inner join table_a a on a.ext_id_a = t.ext_id_a
inner join table_b b on b.ext_id_b = t.ext_id_b
merge into junction_table as jt
using #final as f
on f.id_a = jt.id_a and f.id_b = tj.id_b
when not matched by target then
insert (id_a, id_b) values (id_a, id_b);
I was thinking about a MERGE statement since my stored procedure receives data in a Table Value Parameters parameter and I also have to check for already existing references.
Is anything I can do to improve insertion of these values?
No need to use the #final table variable:
; with cte as (
select tA.id_A, tB.id_B
from #temp t
join table_A tA on t.ext_id_a = tA.ext_id_A
join table_B tB on t.ext_id_B = tB.ext_id_B
)
merge into junction_table
using cte
on cte.id_A = junction_table.id_A and cte.id_B = junction_table.id_B
when not matched by target then
insert (id_A, id_B) values (cte.id_A, cte.id_B);
I am performing a SELECT on two tables, the selection is conditional on the tables' primary ID, so I expect at most 1 result from each query. I'd like to combine the queries into a single SELECT statement. I thought I should do this using a RIGHT (or maybe a LEFT) OUTER JOIN, but this isn't working for me. Any suggestions?
Table A Table B
--------- ----------
ID (pk) | AAttr ID (pk) | BAttr
SELECT AAttr, BAttr
FROM A
RIGHT OUTER JOIN B
ON B.ID = 1
WHERE A.ID = 1
*Edited to include sample cases
For example, if the tables contained the first set of data and querying for an ID of 1, I'd expect:
[null, 'b']
For the second set of data and querying for an ID of 1, I'd expect:
['a', null]
And for the third set of data and querying for an ID of 1, I'd expect:
['a', 'b']
Table A Table B
-------- --------
2 | a 1 | b
3 | c 4 | d
Table A Table B
-------- --------
1 | a 2 | b
3 | c 4 | d
Table A Table B
-------- --------
1 | a 1 | b
3 | c 4 | d
When you join to tables, you need to relate them to each other via a common column. In this case, the ID.
SELECT a.AAttr, b.BAttr
FROM a
LEFT JOIN b
ON a.ID = b.ID
WHERE a.ID = 1;
if IDs in each table are unrelated and you want to combine two unrelated select statements, try this
select
(SELECT top 1 AAttr FROM A where ID = 1) as AAttr,
(SELECT top 1 BAttr FROM B where ID = 1) as BAttr
I have to just insert the value from one table into another but the condition is that out of same id I have to select that one having maximum date and then insert into another. like :
table 1
a | b
1 | 12/1/13
1 | 18/1/13
2 | 2/4/13
2 | 9/8/13
table 2
a | b
1 | 18/1/13
2 | 9/8/13
please suggest the SQL query for it
Could you try :
INSERT INTO Table2 (idcolumn, datecolumn)
SELECT DISTINCT idcolumn, datecolumn
FROM Table1
GROUP BY idcolumn
ORDER BY datecolumn DESC
INSERT INTO table2(a,b)
SELECT a, MAX(b) AS b
FROM table1
GROUP BY a;
I've searched high and low for an answer to this so apologies if it's already answered!
I have the following result from a query in SQL 2005:
ID
1234
1235
1236
1267
1278
What I want is
column1|column2|column3|column4|column5
---------------------------------------
1234 |1235 |1236 |1267 |1278
I can't quite get my head around the pivot operator but this looks like it's going to be involved. I can work with there being only 5 rows for now but a bonus would be for it to be dynamic, i.e. can scale to x rows.
EDIT:
What I'm ultimately after is assigning the values of each resulting column to variables, e.g.
DECLARE #id1 int, #id2 int, #id3 int, #id4 int, #id5 int
SELECT #id1 = column1, #id2 = column2, #id3 = column3, #id4 = column4,
#id5 = column5 FROM [transposed_table]
You also need a value field in your query for each id to aggregate on. Then you can do something like this
select [1234], [1235]
from
(
-- replace code below with your query, e.g. select id, value from table
select
id = 1234,
value = 1
union
select
id = 1235,
value = 2
) a
pivot
(
avg(value) for id in ([1234], [1235])
) as pvt
I think you'll find the answer in this answer to a slightly different question: Generate "scatter plot" result of members against sets from SQL query
The answer uses Dynamic SQL. Check out the last link in mellamokb's answer: http://www.sqlfiddle.com/#!3/c136d/14 where he creates column names from row data.
In case you have a grouped flat data structure that you want to group transpose, like such:
GRP | ID
---------------
1 | 1234
1 | 1235
1 | 1236
1 | 1267
1 | 1278
2 | 1234
2 | 1235
2 | 1267
2 | 1289
And you want its group transposition to appear like:
GRP | Column 1 | Column 2 | Column 3 | Column 4 | Column 5
-------------------------------------------------------------
1 | 1234 | 1235 | 1236 | 1267 | 1278
2 | 1234 | 1235 | NULL | 1267 | NULL
You can accomplish it with a query like this:
SELECT
Column1.ID As column1,
Column2.ID AS column2,
Column3.ID AS column3,
Column4.ID AS column4,
Column5.ID AS column5
FROM
(SELECT GRP, ID FROM FlatTable WHERE ID = 1234) AS Column1
LEFT OUTER JOIN
(SELECT GRP, ID FROM FlatTable WHERE ID = 1235) AS Column2
ON Column1.GRP = Column2.GRP
LEFT OUTER JOIN
(SELECT GRP, ID FROM FlatTable WHERE ID = 1236) AS Column3
ON Column1.GRP = Column3.GRP
LEFT OUTER JOIN
(SELECT GRP, ID FROM FlatTable WHERE ID = 1267) AS Column4
ON Column1.GRP = Column4.GRP
LEFT OUTER JOIN
(SELECT GRP, ID FROM FlatTable WHERE ID = 1278) AS Column5
ON Column1.GRP = Column5.GRP
(1) This assumes you know ahead of time which columns you will want — notice that I intentionally left out ID = 1289 from this example
(2) This basically uses a bunch of left outer joins to append 1 column at a time, thus creating the transposition. The left outer joins (rather than inner joins) allow for some columns to be null if they don't have corresponding values from the flat table, without affecting any subsequent columns.