I have a table holding periods and prices, something like this
itemid periodid periodstart periodend price
1 1 2011/01/01 2011/05/01 50.00
1 2 2011/05/02 2011/08/01 80.00
1 3 2011/08/02 2011/12/31 50.00
Now I have a second table that can hold single dates or periods
itemid periodid periodstart periodend price
1 8 2011/07/01 2011/07/17 70.00
Now, how can I do a query that would return the following result?
itemid periodid periodstart periodend price
1 1 2011/01/01 2011/05/01 50.00
1 2 2011/05/02 2011/06/30 80.00 ****
1 8 2011/07/01 2011/07/17 70.00 ***
1 2 2011/07/18 2011/08/01 80.00 ****
1 3 2011/08/02 2011/12/31 50.00
EDIT -- Highlight the fact that the merge is modifying the dates around it
How about something like
select
t1.itemid,t1.periodid,t1.periodstart, coalesce(dateadd(d,-1,t2.periodstart),t1.periodend) as periodend, t1.price
from t1
left outer join t2 on t1.periodstart < t2.periodstart and t1.periodend>t2.periodstart and t1.itemid=t2.itemid
union
select
t2.itemid,t2.periodid,t2.periodstart, t2.periodend, t2.price
from t1
inner join t2 on t1.periodstart < t2.periodstart and t1.periodend>t2.periodstart and t1.itemid=t2.itemid
union
select
t1.itemid,t1.periodid,dateAdd(d,1,t2.periodend), t1.periodend, t1.price
from t1
inner join t2 on t1.periodstart < t2.periodend and t1.periodend>t2.periodend and t1.itemid=t2.itemid
order by periodstart
Use a Union?
Select itemid, periodid,periodstart, periodend,price FROM table1
UNION
SELECT itemid, periodid,periodstart, periodend,price FROM table2
Are you trying to do some sort of join though? the result set doesn't match the two tables you supplied.
Are you accounting for entries that line up or are you just trying to combine the rows?
if the latter, you could just do a Union
Select itemid, periodid, periodstart, periodend, price
From Table1
Union
Select itemid, periodid, periodstart, periodend, price
From Table2
Related
I want to group the records by relation.
products table:
id
price
1
100
2
200
3
300
4
400
product_properties table:
id
productId
propertyId
1
1
2
2
1
3
3
2
2
4
2
3
5
3
4
6
4
4
The query should select lowest price group by product_properties. I mean, If products have same properties in product_properties, query should return product that has lowest price.
So, For these tables query should return products that have ids 1,3.
I use TypeORM, I tried join the relation and distinct on relation alias name but its not worked.
How can I achieve this?
I wrote two variants query for you:
-- variant 1
select distinct t1.product_id from (
select
pr.price, pp.product_id, pp.property_id, min(pr.price) OVER(PARTITION BY pp.property_id) as min_price
from
test.product_properties pp
inner join
test.products pr on pp.product_id = pr.id
) t1
where
t1.price = t1.min_price;
-- variant 2
select distinct t1.product_id from test.product_properties t1
inner join test.products t2 on t1.product_id = t2.id
inner join (
select
pp.property_id, min(pr.price) as min_price
from
test.product_properties pp
inner join
test.products pr on pp.product_id = pr.id
group by pp.property_id
) t3 on t3.property_id = t1.property_id and t3.min_price = t2.price;
Given two tables t1 and t2 with the same column names:
places, visits, and types_of_events
The output table should have places in the first column.
The second column should have types_of_events from t2.
Use a union along with a computed column to keep track of the table source:
SELECT
var1,
COUNT(CASE WHEN src = 1 THEN 1 END) AS cnt_1,
COUNT(CASE WHEN src = 2 THEN 1 END) AS cnt_2
FROM
(
SELECT var1, id, 1 AS src FROM t1
UNION ALL
SELECT var1, id, 2 FROM t2
) t
GROUP BY
var1;
For an explanation, the inner union query brings together the two data sets, however introducing an src column which is either 1 or 2, corresponding to the table source. Then, in the outer query, we aggregate by var1 and take separate conditional counts of the ids for each table.
I would use union all, but with this twist:
select var1, sum(cnt1), sum(cnt2)
from ((select var1, count(*) as cnt1, 0 as cnt2
from t1
group by var1
) union all
(select var1, 0, count(*)
from t2
group by var1
)
) t
group by var1;
The idea is that by repeating columns, you can avoid the case in the outer query. You can also write this using full join. In Standard SQL, this looks like:
select *
from (select var1, count(*) as cnt1, 0 as cnt2
from t1
group by var1
) t1 full join
(select var1, 0, count(*)
from t2
group by var1
)
using (var1);
However, not all databases support this syntax.
This gives you the number of distinct IDs (per table) associated to each unique var1:
SELECT
COALESCE(t1.var1, t2.var1) var1,
COUNT(DISTINCT t1.id) count1,
COUNT(DISTINCT t2.id) count2
FROM
t1
FULL JOIN t2
ON t1.var1 = t2.var1
GROUP BY
COALESCE(t1.var1, t2.var1);
Result:
var1
count1
count2
A
2
2
B
1
4
C
2
1
D
0
1
I have 2 tables
students:
id | name | age
1 abc 20
2 xyz 21
scores:
id | studentid | marks
1 1 20
2 2 22
3 2 20
4 1 22
5 1 20
where studentid is foreign key to students table
When a do
select studentid
from scores
where marks=20;
I get the following result
1, 2, 1
But if want the name of the student name and when I do a join using
select t1.name
from students t1
inner join scores t2 on t1.id = t2.studentid
where t2.marks=20;
I get xyz,abc,abc Though the ouput is correct is there any way I can maintain the order in which scores are listed in the scores table? I should get abc,xyz,abc as output. I tried using subquery as well
SELECT name
FROM students
WHERE ID IN ( select studentid from scores where marks=20) ;
but that also did not give me correct order. How can this be achieved using CTEs (common table expressions)? I tried the follownig cte but it did not work
with cte as(
select t2.id, t1.name
from students t1
inner join scores t2 on t1.id = t2.studentid
where t2.marks=20)
select name from cte order by id
You can order by a column not present in select list:
select t1.name
from students t1
inner join scores t2 on t1.id = t2.student_id
where t2.marks=20
order by t2.id;
name
------
abc
xyz
abc
(3 rows)
I am stuck at this T-SQL query.
I have table below
Age SectioName Cost
---------------------
1 Section1 100
2 Section1 200
1 Section2 500
3 Section2 100
4 Section2 200
Lets say for each section I can have maximum 5 Age. In above table there are some missing Ages. How do I insert missing Ages for each section. (Possibly without using cursor). The cost would be zero for missing Ages
So after the insertion the table should look like
Age SectioName Cost
---------------------
1 Section1 100
2 Section1 200
3 Section1 0
4 Section1 0
5 Section1 0
1 Section2 500
2 Section2 0
3 Section2 100
4 Section2 200
5 Section2 0
EDIT1
I should have been more clear with my question. The maximum age is dynamic value. It could be 5,6,10 or someother value but it will be always less than 25.
I think I got it
;WITH tally AS
(
SELECT 1 AS r
UNION ALL
SELECT r + 1 AS r
FROM tally
WHERE r < 5 -- this value could be dynamic now
)
select n.r, t.SectionName, 0 as Cost
from (select distinct SectionName from TempFormsSectionValues) t
cross join
(select ta.r FROM tally ta) n
where not exists
(select * from TempFormsSectionValues where YearsAgo = n.r and SectionName = t.SectionName)
order by t.SectionName, n.r
You can use this query to select missing value:
select n.num, t.SectioName, 0 as Cost
from (select distinct SectioName from table1) t
cross join
(select 1 as num union select 2 union select 3 union select 4 union select 5) n
where not exists
(select * from table1 where table1.age = n.num and table1.SectioName = t.SectioName)
It creates a Cartesian product of sections and numbers 1 to 5 and then selects those that doesn't exist yet. You can then use this query for the source of insert into your table.
SQL Fiddle (it has order by added to check the results easier but it's not necessary for inserting).
Use below query to generate missing rows
SELECT t1.Age,t1.Section,ISNULL(t2.Cost,0) as Cost
FROM
(
SELECT 1 as Age,'Section1' as Section,0 as Cost
UNION
SELECT 2,'Section1',0
UNION
SELECT 3,'Section1',0
UNION
SELECT 4,'Section1',0
UNION
SELECT 5,'Section1',0
UNION
SELECT 1,'Section2',0
UNION
SELECT 2,'Section2',0
UNION
SELECT 3,'Section2',0
UNION
SELECT 4,'Section2',0
UNION
SELECT 5,'Section2',0
) as t1
LEFT JOIN test t2
ON t1.Age=t2.Age AND t1.Section=t2.Section
ORDER BY Section,Age
SQL Fiddle
You can utilize above result set for inserting missing rows by using EXCEPT operator to exclude already existing rows in table -
INSERT INTO test
SELECT t1.Age,t1.Section,ISNULL(t2.Cost,0) as Cost
FROM
(
SELECT 1 as Age,'Section1' as Section,0 as Cost
UNION
SELECT 2,'Section1',0
UNION
SELECT 3,'Section1',0
UNION
SELECT 4,'Section1',0
UNION
SELECT 5,'Section1',0
UNION
SELECT 1,'Section2',0
UNION
SELECT 2,'Section2',0
UNION
SELECT 3,'Section2',0
UNION
SELECT 4,'Section2',0
UNION
SELECT 5,'Section2',0
) as t1
LEFT JOIN test t2
ON t1.Age=t2.Age AND t1.Section=t2.Section
EXCEPT
SELECT Age,Section,Cost
FROM test
SELECT * FROM test
ORDER BY Section,Age
http://www.sqlfiddle.com/#!3/d9035/11
I am teaching myself T-SQL and am struggling to comprehend the following example..
Suppose you want to display several nonaggregated columns along with
some aggregate expressions that apply to the entire result set or to a
larger grouping level. For example, you may need to display several
columns from the Sales.SalesOrderHeader table and calculate the
percent of the TotalDue for each sale compared to the TotalDue for all
the customer’s sales. If you group by CustomerID, you can’t include
other nonaggregated columns from Sales.SalesOrderHeader unless you
group by those columns. To get around this, you can use a derived
table or a CTE.
Here are two examples given...
SELECT c.CustomerID, SalesOrderID, TotalDue, AvgOfTotalDue,
TotalDue/SumOfTotalDue * 100 AS SalePercent
FROM Sales.SalesOrderHeader AS soh
INNER JOIN
(SELECT CustomerID, SUM(TotalDue) AS SumOfTotalDue,
AVG(TotalDue) AS AvgOfTotalDue
FROM Sales.SalesOrderHeader
GROUP BY CustomerID) AS c ON soh.CustomerID = c.CustomerID
ORDER BY c.CustomerID;
WITH c AS
(SELECT CustomerID, SUM(TotalDue) AS SumOfTotalDue,
AVG(TotalDue) AS AvgOfTotalDue
FROM Sales.SalesOrderHeader
GROUP BY CustomerID)
SELECT c.CustomerID, SalesOrderID, TotalDue,AvgOfTotalDue,
TotalDue/SumOfTotalDue * 100 AS SalePercent
FROM Sales.SalesOrderHeader AS soh
INNER JOIN c ON soh.CustomerID = c.CustomerID
ORDER BY c.CustomerID;
Why doesn't this query produce the same result..
SELECT CustomerID, SalesOrderID, TotalDue, AVG(TotalDue) AS AvgOfTotalDue,
TotalDue/SUM(TotalDue) * 100 AS SalePercent
FROM Sales.SalesOrderHeader
GROUP BY CustomerID, SalesOrderID, TotalDue
ORDER BY CustomerID
I'm looking for someone to explain the above examples in another way or step through it logically so I can understand how they work?
The aggregates in this statement (i.e. SUM and AVG) don't do anything:
SELECT CustomerID, SalesOrderID, TotalDue, AVG(TotalDue) AS AvgOfTotalDue,
TotalDue/SUM(TotalDue) * 100 AS SalePercent
FROM Sales.SalesOrderHeader
GROUP BY CustomerID, SalesOrderID, TotalDue
ORDER BY CustomerID
The reason for this is you're grouping by TotalDue, so all records in the same group have the same value for this field. In the case of AVG this means you're guarenteed for AvgOfTotalDue to always equal TotalDue. For SUM it's possible you'd get a different result, but as you're also grouping by SalesOrderID (which I'd imagine is unique in the SalesOrderHeader table) you will only have one record per group, so again this will always equal the TotalDue value.
With the CTE example you're only grouping by CustomerId; as a customer may have many sales orders associated with it, these aggregate values will be different to the TotalDue.
EDIT
Explanation of the aggregate of field included in group by:
When you group by a value, all rows with that same value are collected together and aggregate functions are performed over them. Say you had 5 rows with a total due of 1 and 3 with a total due of 2 you'd get two result lines; one with the 1s and one with the 2s. Now if you perform a sum on these you have 3*1 and 2*2. Now divide by the number of rows in that result line (to get the average) and you have 3*1/3 and 2*2/2; so things cancel out leaving you with 1 and 2.
select totalDue, avg(totalDue)
from (
select 1 totalDue
union all select 1 totalDue
union all select 1 totalDue
union all select 2 totalDue
union all select 2 totalDue
) x
group by totalDue
select uniqueId, totalDue, avg(totalDue), sum(totalDue)
from (
select 1 uniqueId, 1 totalDue
union all select 2 uniqueId, 1 totalDue
union all select 3 uniqueId, 1 totalDue
union all select 4 uniqueId, 2 totalDue
union all select 5 uniqueId, 2 totalDue
) x
group by uniqueId
Runnable Example: http://sqlfiddle.com/#!2/d41d8/21263