I have a table like:
ID | LABEL | SOME_VALUE
1 a rand_1
2 a NULL
3 b rand_9
4 c rand_3
5 c rand_3
6 c rand_3
7 d NULL
8 d rand_4
As you can see, ID is unique, label is not unique (can be 1 or more) and some_value is also not unique.
What I want to do is the following:
I want to get a unique list of LABELS, which exist in the database in more than one rows (min 2) and of which rows has SOME_VALUE not NULL.
So I would get:
ID | LABEL | SOME_VALUE
1 a rand_1
2 a NULL
7 d NULL
8 d rand_4
in return.
How can I achieve this?
There are two versions. First one does exactly as listed in results, eliminating rand_3 because even though it appears three times all the values are the same (I don't see distinct condition specified in question).
There must be a better way, but as they say I can't brain today, I have the dumb :-)
select *
from tbl
inner join
(
select label
FROM tbl
GROUP BY Label
HAVING count (distinct some_value)
+ sum(distinct case when some_value is null then 1 else 0 end) > 1
) a
on tbl.label = a.label
Second one retrieves C also following the requirements (some_value being not null for at least one of some_value).
select *
from tbl
inner join
(
select label
FROM tbl
GROUP BY Label
HAVING count(*) > 1 and count(some_value) > 0
) a
on tbl.label = a.label
And there is Sql Fiddle.
The HAVING parameter limits grouped items:
SELECT
Label
FROM dbo.TableName
WHERE NOT Some_Value IS NULL
GROUP BY Label
HAVING COUNT(*) > 2
SELECT t1.*
FROM yourTable t1
JOIN yourTable t2
ON t1.LABEL = t2.LABEL
AND t1.ID < t2.ID
WHERE t1.SOME_VALUE IS NOT NULL
OR t2.SOME_VALUE IS NOT NULL
This should work -
SELECT test.*
FROM (
SELECT label
FROM test
GROUP BY Label
HAVING COUNT(DISTINCT IFNULL(some_value, '~null~')) > 1
) AS tmp
INNER JOIN test
ON tmp.label = test.label;
Related
I have the following data:
id userid name group
1 1 A x
2 1 A y
3 1 A z
4 2 B x
5 2 B y
6 3 C y
7 4 D x
8 5 E x
9 5 E z
10 6 F x
I want to find those records that meet all this condition:
Select all rows where the a userid belongs to a group other than y but the userid also belongs to group y.
The resulting dataset will be as follows:
id userid name group
1 1 A x
3 1 A z
4 2 B x
If you see, it has resulted in two records for userid a because these are two two records belong to groups other than y but the userid 1 also belongs to group y. Same for userid 2.
I have been breaking my head on how to get this in an SQL statement but not even close to a solution.
Any help is appreciated.
Use a join:
SELECT t1.*
FROM mytable t1
INNER JOIN mytable t2
ON t1.user_id = t2.user_id AND t1.group <> t2.group AND t2.group = 'y'
I think that would be the fastest query (but please feel free to try the other solutions as well).
Add an index on user_id if not already there and maybe play with some other indexes as well (maybe a composite index on group and user_id can be utilized)
Use exists
select *
from MyTable a2
where name_group <> 'y'
and exists (select 1
from MyTable a2
where a2.name_group = 'y'
and a2.userid = a1.userid)
You can get all the users that meet the condition using aggregation and having:
select userid
from t
group by userid
having sum( group = 'y' ) > 0 and
sum( group <> 'y') > 0;
I leave it to your to put this into a query to get all the original rows.
Im creating a query that select two tables and create a total variable by count a field in one table.
Example:
Table A:
ID | email
1 | test#test
2 | test2#test
3 | test3#test
Table B
ID | email_id | username_id
1 | 1 | 11
2 | 1 | 22
3 | 2 | 33
My query:
select a.id, a.email, count(c.id) as total
from tableA a
left join tableC c on c.email_id = a.id AND total <= 5
group by a.email LIMIT 1
Output:
Unknown column 'total' in 'on clause
I need to select the first "a.id" that has total <= 5. How can I do it?
Logically Select is processed after the Where clause so you cannot use Alias name in same Where clause.
Use HAVING clause
select a.id, a.email, count(c.id) as total
from tableA a
left join tableC c on c.email_id = a.id
group by a.email
Having count(c.id) <= 5
LIMIT 1
I think Mysql allows you do this as well
Having total <= 5
Try HAVING Count(c.id) <= 5
Just to make this a bit clearer, since the correct answer has already been provided - You don't have to use the HAVING clause, and the HAVING clause is not always the solution for this problem.
The HAVING clause is usually used to place filters on aggregated columns (sum,count,max,min etc..) , but when you have a calculated column (colA + colB as calc_column for example) , then another approach , which should work here as well is to wrap the query with another select, and then the new column will be available on the WHERE :
SELECT *
FROM (The query here ) s
WHERE s.total <= 5
I have a table where I can store the same name with different states.
|ID|name|state
1 A 1
2 A 2
3 B 3
4 C 1
There 3 states 1,2,3.
How can I find those records which has no state 3, maximum 2?
In this example A and C has no state 3 so they would be the result of the query:
SELECT * FROM `records` WHERE (`state_id`!=3)
It only returns rows without state 3 but it can be that value.
http://www.sqlfiddle.com/#!9/35dbe/2
SELECT r.*
FROM `records` r
LEFT JOIN `records` r3
ON r.name = r3.name
AND r3.state=3
WHERE r3.state IS NULL
How about a DISTINCT and NOT IN?
Something like
SELECT DISTINCT Name
FROM Table1 t
WHERE Name NOT IN (
SELECT Name
FROM Table1 s
WHERE s.State = 3)
SQL Fiddle DEMO
You can do this with conditional aggregation:
select name from t
group by name
having sum(case when state = 3 then 1 else 0 end) = 0
Fiddle http://sqlfiddle.com/#!9/a8bb5/2
I have a table with two sets of integer values. Using MySQL I want to display all of the rows that correspond to unique entries in the second column. Basically I can have duplicate A values, but only unique B values. If there are duplicates for a value in B, remove all the results with that value. If I use DISTINCT I will still get one of those duplicates which I do not want. I also want to avoid using COUNT(). Here's an example:
|_A____B_|
| 1 2 |
| 1 3 |
| 2 2 |
| 2 4 |
| 1 4 |
| 5 5 |
Will have the following Results (1,3), (5,5). Any value in B that has a duplicate is removed.
Try this
SELECT * FROM TEMP WHERE B IN (
SELECT B FROM TEMP GROUP BY B Having COUNT(B)=1
);
I know you want to avoid using COUNT() but this is the quick solution.
working fiddle here - http://sqlfiddle.com/#!9/29d16/8
Tested and works! you need atleast count(*) to count the values
select * from test where B in (
select B from test group by B having count(*)<2
)
I don't know why you want to avoid using count(), because that's what would do the trick as follows:
Let's say your table is named "mytable"
SELECT t1.A, t1.B
FROM mytable t1
JOIN (
SELECT B, count(*) AS B_INSTANCES
FROM mytable
GROUP BY B
HAVING count(*) = 1
) t2 ON t2.B = t1.B
ORDER BY t1.A, t1.B
Hi there m trying to calculate the row count for same value,
id,value
1 | a
2 | b
3 | c
4 | d
5 | e
and my query is
select value, count(*) as Count from mytable where id in('4','2','4','1','4') group by value having count(*) > 1
for which my expected output will be,
value,Count
d | 3
b | 1
a | 1
Thanks, any help will be appreciated
Try that:
SELECT value, count(value) AS Count
FROM mytable m
WHERE value = m.value
GROUP BY value
SELECT t.id, t.value, COUNT(t.id)
FROM
test t
JOIN
( SELECT 1 AS id
UNION ALL SELECT 3
UNION ALL SELECT 3
UNION ALL SELECT 4
UNION ALL SELECT 1
UNION ALL SELECT 1 ) AS tmp
ON t.id = tmp.id
GROUP BY t.id
Sample on sqlfiddle.com
See also: Force MySQL to return duplicates from WHERE IN clause without using JOIN/UNION?
Of course, your IN parameter will be dynamic, and thus you will have to generate the corresponding SQL statement for the tmp table.
That's the SQL-only way to do it. Another possibility is to have the query like you have it in your question and afterwards programmatically associate the rows to the count passed to the IN parameter.