If i have 4 rows and want to select rows based on a single column's distinct values and dont mind which info it uses for the rest of the row, how do i do this? There doesn't seem to be a 'distinct' function for single cols whilst maintaining rest of row data.
eg
Name, value
john 1
john 2
michael 3
michael 5
result
john 1
michael 5
note it could have been john 2 or michael 3, i dont care which row for John or Michael it uses for the rest of the values.
GROUP BY Name and use any aggregate function with the value MIN or MAX since you don't care about the value of it:
SELECT Name, MIN(value)
FROM table
GROUP BY Name
Try this
select a.* from TAbleName a
inner join
(
select distinct name,min(Id) as id from TAbleName
group by name
) as b
on a.name= b.name
and a.id=b.id
Related
I have the following table:
ID | DATES
---+-----------
1 02-09-2010
2 03-08-2011
1 08-01-2011
3 04-03-2010
I am looking for IDs who had at least one date before 05-01-2010 AND at least one date after 05-02-2010
I tried the following:
WHERE tb1.DATES < '05-01-2010' AND tb1.DATES > '05-02-2010'
I don't think it's correct because I wasn't getting the right IDs when I did that and there's something wrong with that logic.
Can someone explain what I am doing wrong here?
The SQL command SELECT * FROM tb1 WHERE tb1.DATES < '05-01-2010' AND tb1.DATES > '05-02-2010' is asking "find all the rows where the 'dates' field is before 1 May and after 2 May" which - when put in English - is obviously none of them.
Instead, the command should be asking "find all the IDs which have a record that is before 1 May, and another record after 2 May" - creating the need to look at multiple records for each ID.
As #Martheen suggested, you could do this with two (sub)queries e.g.,
SELECT A.ID
FROM
(SELECT DISTINCT tb1.ID
FROM mytable tb1
WHERE tb1.[dates] < '20100501'
) AS A
INNER JOIN
(SELECT DISTINCT tb1.ID
FROM mytable tb1
WHERE tb1.[dates] > '20100502'
) AS B
ON A.ID = B.ID;
or using INTERSECT
SELECT DISTINCT tb1.ID
FROM mytable tb1
WHERE tb1.[dates] < '20100501'
INTERSECT
SELECT mt2.ID
FROM mytable mt2
WHERE mt2.[dates] > '20100502';
The use of DISTINCT in the above is so that you only get one row per ID, no matter how many rows they have before/after the relevant dates.
You could also do it via GROUP BY and HAVING - which in this particular case is easy as if any dates are before 1 May, then their earliest date must be before 1 May (and correspondingly for their max data and 2 May) e.g.,
SELECT mt1.ID
FROM mytable mt1
GROUP BY mt1.ID
HAVING MIN(mt1.[dates]) < '20100501' AND MAX(mt1.[dates]) > '20100502';
Here is a db<>fiddle with all 3 of these; all provide the same answer (one row, with ID = 1).
Finally, you should use an unambiguous format for your dates. My preferred one of these is 'yyyyMMdd' with no dashes/slashes/etc (as these make them ambiguous).
Different countries/servers/etc will convert the dates you have there differently e.g., SQL Server UTC string comparison not working
This is one solution to use between to specify range.
SELECT * from Table_name where
From_date BETWEEN '2013-01-03'AND '2013-01-09'
Other solution is to what you mentioned but see that the logic is correct
SELECT * from Table_name where
From_date > '2010-01-05'AND From_date <'2010-02-05'
I have a table for company phone numbers and one of the columns is IsPrimary which is a boolean type. The table looks like this:
CompanyId | AreaCode | PhoneNumber | IsPrimary
123 212 555-1212 0
234 307 555-1234 1
234 307 555-4321 0
As you can see in the first record, even though the phone number is the only one for CompanyId: 123, it's not marked as the primary.
In such cases, I want my SELECT statement to return the first available number for that company.
My current SELECT statement looks like this which does NOT return a number unless it's set as the primary number.
SELECT *
FROM CompanyPhoneNumbers AS t
WHERE t.IsPrimary = 1
How can I modify this SELECT statement so that it includes the phone number for CompanyId: 123?
The query might be different depending on what you are actually up to.
If you already have the CompanyId and only need the phone number for it, that's easy:
select top (1) pn.*
from dbo.CompanyPhoneNumbers pn
where pn.CompanyId = #CompanyId -- A parameter provided externally, by calling code for instance
order by pn.IsPrimary desc;
However, if you need all companies' data, including one of their phones (for example, you might be going to create a view for this), then you need a correlated subquery:
select c.*, oa.*
from dbo.Companies c
outer apply (
select top (1) pn.*
from dbo.CompanyPhoneNumbers pn
where pn.CompanyId = c.Id
order by pn.IsPrimary desc
) oa;
I have deliberately used outer instead of cross apply, otherwise it will filter out companies with no phone numbers listed.
You can achieve this using an apply statement. This looks at the exact same table and returns the record with the highest IsPrimary so, this would return the records with a 1 in that column. If there are more than one marked as primary or not as primary, then it returns the phone number, with area code, in ascending order.
select b.*
from CompanyPhoneNumbers a
cross apply (
select top 1
*
from CompanyPhoneNumbers b
where b.CompanyId = a.CompanyId
order by b.IsPrimary desc
,b.AreaCode
,b.PhoneNumber
) b
This is my first post - so I apologise if it's in the wrong seciton!
I'm joining two tables with a one-to-many relationship using their respective ID numbers: but I only want to return the most recent record for the joined table and I'm not entirely sure where to even start!
My original code for returning everything is shown below:
SELECT table_DATES.[date-ID], *
FROM table_CORE LEFT JOIN table_DATES ON [table_CORE].[core-ID] = table_DATES.[date-ID]
WHERE table_CORE.[core-ID] Like '*'
ORDER BY [table_CORE].[core-ID], [table_DATES].[iteration];
This returns a group of records: showing every matching ID between table_CORE and table_DATES:
table_CORE date-ID iteration
1 1 1
1 1 2
1 1 3
2 2 1
2 2 2
3 3 1
4 4 1
But I need to return only the date with the maximum value in the "iteration" field as shown below
table_CORE date-ID iteration Additional data
1 1 3 MoreInfo
2 2 2 MoreInfo
3 3 1 MoreInfo
4 4 1 MoreInfo
I really don't even know where to start - obviously it's going to be a JOIN query of some sort - but I'm not sure how to get the subquery to return only the highest iteration for each item in table 2's ID field?
Hope that makes sense - I'll reword if it comes to it!
--edit--
I'm wondering how to integrate that when I'm needing all the fields from table 1 (table_CORE in this case) and all the fields from table2 (table_DATES) joined as well?
Both tables have additional fields that will need to be merged.
I'm pretty sure I can just add the fields into the "SELECT" and "GROUP BY" clauses, but there are around 40 fields altogether (and typing all of them will be tedious!)
Try using the MAX aggregate function like this with a GROUP BY clause.
SELECT
[ID1],
[ID2],
MAX([iteration])
FROM
table_CORE
LEFT JOIN table_DATES
ON [table_CORE].[core-ID] = table_DATES.[date-ID]
WHERE
table_CORE.[core-ID] Like '*' --LIKE '%something%' ??
GROUP BY
[ID1],
[ID2]
Your example field names don't match your sample query so I'm guessing a little bit.
Just to make sure that I have everything you’re asking for right, I am going to restate some of your question and then answer it.
Your source tables look like this:
table_core:
table_dates:
And your outputs are like this:
Current:
Desired:
In order to make that happen all you need to do is use a subquery (or a CTE) as a “cross-reference” table. (I used temp tables to recreate your data example and _ in place of the - in your column names).
--Loading the example data
create table #table_core
(
core_id int not null
)
create table #table_dates
(
date_id int not null
, iteration int not null
, additional_data varchar(25) null
)
insert into #table_core values (1), (2), (3), (4)
insert into #table_dates values (1,1, 'More Info 1'),(1,2, 'More Info 2'),(1,3, 'More Info 3'),(2,1, 'More Info 4'),(2,2, 'More Info 5'),(3,1, 'More Info 6'),(4,1, 'More Info 7')
--select query needed for desired output (using a CTE)
; with iter_max as
(
select td.date_id
, max(td.iteration) as iteration_max
from #table_dates as td
group by td.date_id
)
select tc.*
, td.*
from #table_core as tc
left join iter_max as im on tc.core_id = im.date_id
inner join #table_dates as td on im.date_id = td.date_id
and im.iteration_max = td.iteration
select *
from
(
SELECT table_DATES.[date-ID], *
, row_number() over (partition by table_CORE date-ID order by iteration desc) as rn
FROM table_CORE
LEFT JOIN table_DATES
ON [table_CORE].[core-ID] = table_DATES.[date-ID]
WHERE table_CORE.[core-ID] Like '*'
) tt
where tt.rn = 1
ORDER BY [core-ID]
I have two tables
table-a
id name
100 asd
101 ass
102 gdd
103 hgf
104 cvd
105 erf
table-b
id filter
100 red
101 blue
100 green
100 yellow
102 black
102 red
103 dark
Table-a is the master table and that have all the id's.but Table two is the one which has 'filter' data.
from these two table I want to find out all those 'id's which does not have minimum 2 filters.
note that table-b does not have all the itemnumbers in table-a, and i want all that itemnumber irrespective of if that is in table-a or table-b.I have tried inner joining these two tables and getting data out but nothing worked.
Select A.ID, A.Name, count(*)
from tableA A
LEFT JOIN tableB B on A.ID = B.ID
Group By A.ID, A.name
having count(*) <= 1
LEFT JOIN gives all records from A and only those in B which match.
The group by ID and name let us count the number of filters found in
each
The having says give me any items with a count less than or
equal to 1. (or less than the minimum 2)
Thus results would be.
101 ass 1
103 hgf 1
104 cvd 0
105 erf 0
select
*
from
table-a a
left join (
select id, count(id) as c from table-b group by id
) v on a.id = v.id
where isnull(v.id, 0) < 2
I think this would work in SQL Server (tested in SQLite and usually the two are fairly compatible when it comes to inline view syntax). But syntax issues aside, inline views can make working with sets easier to visualize.
select TA.id, name
from TA
inner join
(
select id from TA
where not exists (select id from TB where TA.id = TB.id)
UNION
select id from TB
group by id having count(filter) < 2
) as FOO
on TA.id = FOO.id
The default behavior of UNION is to remove duplicates.
The first UNIONed set consists of the ids from table A that have no filter (no counterpart in the filters table B).
The second UNIONed set consists of the ids from the filters table, table B, that have only 1 filter.
We inner join those unioned sets back to Table A to get the entity Name.
TABLE A
ID Name Age
1 John 22
TABLE B
ID Name
5 Erik
I want result like
ID Name Age
1 John 22
5 Erik
When I am performing UNION giving error
"All queries combined using a UNION, INTERSECT or EXCEPT operator must have an equal number of expressions in their target lists."
How to get desired result?
You could supply a dummy column in lieu of the missing one that returns NULL as below.
SELECT ID,
Name,
Age
FROM TABLE_A
UNION ALL
SELECT ID,
Name,
NULL
FROM TABLE_B