I want to pull data from my table.
line Entryid
hello 1
world 1
this 1
is 1
hello 2
again 2
world 2
I want to select all the information associated with Entryid 2. Note i cannot say WHERE Project id = 2. I need something like where MAX(Entryid). So the information pulled will be hello again world
You can do what you want using join or a subquery:
select t.*
from t
where t.entryid = (select max(t2.entryid) from t t2);
You can use a sub query.
Select * From yourTable Where Entryid = (Select max (Entryid) From yourTable)
Related
I am pretty new to SQL and I thought I was comfortable using it after a while but it still is tough. I am trying to increment ids. I know I could use auto-increment but in this case there are id has relationship with several categories so it has to start with different numbers so I can't do it.
The table looks something like this:
id category
----------------
1000 1
1000 1
...
2000 2
2000 2
...
And I want to make it:
id category
------------------
1000 1
1001 1
1002 1
...
2000 2
2001 2
...
I tried:
UPDATE T1
SET id = CASE
WHEN EXISTS (SELECT id FROM STYLE WHERE T1.id = id)
THEN (SELECT MAX(CAST(id AS INT)) + 1
FROM STYLE
WHERE category = T1.category)
END
FROM STYLE T1
WHERE idStyle = idStyle
But it just added 1 to all rows. How could I go 1 by 1 so it could actually get the incremented max id? Thank you.
In the absense of real sample data, this is a pseudo-sql, however, something like...
UPDATE YT
----SELECT NULL as Ihave no context of other fields in your table
SET id = id + ROW_NUMBER() OVER (PARTITION BY category ORDER BY (SELECT NULL)) - 1
FROM YourTable YT;
You can use row_number() function instead :
select *,
concat(cid, row_number() over (partition by id order by category)-1) as NewId
from style s;
I have a table that looks like the following but also has more columns that are not needed for this instance.
ID DATE Random
-- -------- ---------
1 4/12/2015 2
2 4/15/2015 2
3 3/12/2015 2
4 9/16/2015 3
5 1/12/2015 3
6 2/12/2015 3
ID is the primary key
Random is a foreign key but i am not actually using table it points to.
I am trying to design a query that groups the results by Random and Date and select the MAX Date within the grouping then gives me the associated ID.
IF i do the following query
select top 100 ID, Random, MAX(Date) from DateBase group by Random, Date, ID
I get duplicate Randoms since ID is the primary key and will always be unique.
The results i need would look something like this
ID DATE Random
-- -------- ---------
2 4/15/2015 2
4 9/16/2015 3
Also another question is there could be times where there are many of the same date. What will MAX do in that case?
You can use NOT EXISTS() :
SELECT * FROM YourTable t
WHERE NOT EXISTS(SELECT 1 FROM YourTable s
WHERE s.random = t.random
AND s.date > t.date)
This will select only those who doesn't have a bigger date for corresponding random value.
Can also be done using IN() :
SELECT * FROM YourTable t
WHERE (t.random,t.date) in (SELECT s.random,max(s.date)
FROM YourTable s
GROUP BY s.random)
Or with a join:
SELECT t.* FROM YourTable t
INNER JOIN (SELECT s.random,max(s.date) as max_date
FROM YourTable s
GROUP BY s.random) tt
ON(t.date = tt.max_date and s.random = t.random)
In SQL Server you could do something like the following,
select a.* from DateBase a inner join
(select Random,
MAX(dt) as dt from DateBase group by Random) as x
on a.dt =x.dt and a.random = x.random
This method will work in all versions of SQL as there are no vendor specifics (you'll need to format the dates using your vendor specific syntax)
You can do this in two stages:
The first step is to work out the max date for each random:
SELECT MAX(DateField) AS MaxDateField, Random
FROM Example
GROUP BY Random
Now you can join back onto your table to get the max ID for each combination:
SELECT MAX(e.ID) AS ID
,e.DateField AS DateField
,e.Random
FROM Example AS e
INNER JOIN (
SELECT MAX(DateField) AS MaxDateField, Random
FROM Example
GROUP BY Random
) data
ON data.MaxDateField = e.DateField
AND data.Random = e.Random
GROUP BY DateField, Random
SQL Fiddle example here: SQL Fiddle
To answer your second question:
If there are multiples of the same date, the MAX(e.ID) will simply choose the highest number. If you want the lowest, you can use MIN(e.ID) instead.
I am selecting all badge numbers from a database where category is equal to 1.
category | badge number
0 | 1
1 | 1
2 | 5
1 | 1
Sometimes the category is duplicated, is there a way to only get unique badge numbers from the database?
So above there is two 1's in category, each with badge number 1. How can I make sure the result only gives '1' rather than '1,1'
Use DISTINCT key word in the SELECT statement.
SELECT DISTINCT badge_number FROM Your_Table WHERE category = 1
Use the distinct keyword in your select.
select distinct badge_number from table_name where category = 1
Have you tried Select Distinct :
SELECT DISTINCT [badge number] from table
where Category=1
http://www.w3schools.com/sql/sql_distinct.asp
Select Distinct Badgenumber from table where Category = 1
SELECT DISTINCT BadgeNumber FROM dbo.TableName
Where Category = 1
Edited:
Ohh, there are so many posts already .... !!
Code Description Whatever
---------------------------------
1 stuff blah
1 something meh
2 yah bong
2 never hammer time
How do I get a results set from this with each Code only present once? (I don't overly care which record for that code it is).
So I want....
1 stuff blah
2 yah bong
SELECT *
FROM (
SELECT * , row_number() over(partition by code order by Description) as id
from yourTable
) temp
WHERE id = 1
I think this is sql server only
You first need to pick a column which determines what counts as 'the first result'. In my example I chose Description:
SELECT * FROM YourTable first
WHERE
(SELECT COUNT(*) FROM YourTable previous
WHERE previous.Code=first.Code AND previous.Description < first.Description) = 0
I have a table in my database:
Name | Element
1 2
1 3
4 2
4 3
4 5
I need to make a query that for a number of arguments will select the value of Name that has on the right side these and only these values.
E.g.:
arguments are 2 and 3, the query should return only 1 and not 4 (because 4 also has 5). For arguments 2,3,5 it should return 4.
My query looks like this:
SELECT name FROM aggregations WHERE (element=2 and name in (select name from aggregations where element=3))
What do i have to add to this query to make it not return 4?
A simple way to do it:
SELECT name
FROM aggregations
WHERE element IN (2,3)
GROUP BY name
HAVING COUNT(element) = 2
If you want to add more, you'll need to change both the IN (2,3) part and the HAVING part:
SELECT name
FROM aggregations
WHERE element IN (2,3,5)
GROUP BY name
HAVING COUNT(element) = 3
A more robust way would be to check for everything that isn't not in your set:
SELECT name
FROM aggregations
WHERE NOT EXISTS (
SELECT DISTINCT a.element
FROM aggregations a
WHERE a.element NOT IN (2,3,5)
AND a.name = aggregations.name
)
GROUP BY name
HAVING COUNT(element) = 3
It's not very efficient, though.
Create a temporary table, fill it with your values and query like this:
SELECT name
FROM (
SELECT DISTINCT name
FROM aggregations
) n
WHERE NOT EXISTS
(
SELECT 1
FROM (
SELECT element
FROM aggregations aii
WHERE aii.name = n.name
) ai
FULL OUTER JOIN
temptable tt
ON tt.element = ai.element
WHERE ai.element IS NULL OR tt.element IS NULL
)
This is more efficient than using COUNT(*), since it will stop checking a name as soon as it finds the first row that doesn't have a match (either in aggregations or in temptable)
This isn't tested, but usually I would do this with a query in my where clause for a small amount of data. Note that this is not efficient for large record counts.
SELECT ag1.Name FROM aggregations ag1
WHERE ag1.Element IN (2,3)
AND 0 = (select COUNT(ag2.Name)
FROM aggregatsions ag2
WHERE ag1.Name = ag2.Name
AND ag2.Element NOT IN (2,3)
)
GROUP BY ag1.name;
This says "Give me all of the names that have the elements I want, but have no records with elements I don't want"