I have two tables with one column each, containing names.
Names can have duplicates. One name can be found on every table or only in one.
I want to make an query that count duplicates, for each name in every table an list these values like this:
| name | table1 | table2 |
| john | 12 | 23 |
| mark | 2 | 5 |
| mary | | 10 |
| luke | 4 | |
I tried different strategies using UNION but no luck.
Thanks in advance!!!
SELECT DISTINCT t1.name, t1.cnt1, t2.cnt2
FROM
(SELECT name,count(name) as cnt1 FROM table1 GROUP BY name) t1
LEFT JOIN
(SELECT name,count(name) as cnt2 FROM table2 GROUP BY name) t2
ON t1.name = t2.name
UNION
SELECT DISTINCT t2.name, t1.cnt1, t2.cnt2
FROM
(SELECT name,count(name) as cnt1 FROM table1 GROUP BY name) t1
RIGHT JOIN
(SELECT name,count(name) as cnt2 FROM table2 GROUP BY name) t2
ON t1.name = t2.name
Here's a simpler solution:
You can UNION the names from the two tables together, manually differentiating their origin tables with a tbl column.
Then it's just a simple GROUP BY with conditional aggregation using the differentiating column:
SELECT a.name,
NULLIF(COUNT(CASE a.tbl WHEN 1 THEN 1 END), 0) AS table1,
NULLIF(COUNT(CASE a.tbl WHEN 2 THEN 1 END), 0) AS table2
FROM
(
SELECT name, 1 AS tbl FROM table1 UNION ALL
SELECT name, 2 FROM table2
) a
GROUP BY a.name
In accordance with your desired result-set, we NULL the count value if it turns out to be 0.
SQLFiddle Demo
SELECT SUM(res.cn), name
FROM
(
SELECT name, count(name) as cn from table1 GROUP BY name HAVING count(name) > 1
UNION ALL
SELECT name, count(name) as cn from table2 GROUP BY name HAVING count(name)>1
) as res
GROUP BY nam
e
Try the above :) I made a fiddle for you to test it:
http://sqlfiddle.com/#!3/796b2/3
It has a few double names in each table and will show you which names have doubles and then print them. The names that only appear once are not shown (acheived by the HAVING clause)
After some reading i don't think that it's posibil what i want to do. This situation ca be solved with pivot table in excel or libreoffice.
In fact this is method that i used, combined with some sql stataments to count occurence of names and export as CSV.
UNION definitetly not work. Some chance are with join, but not shure.
I found a post that discusses the same problem as mine.
MySQL - Rows to Columns
Related
+------+-------+
| name | value |
+======+=======+
| 5 | 0 |
+------+-------+
| 4 | 0 |
+------+-------+
| 3 | 1 |
+------+-------+
| 4 | 1 |
+------+-------+
| 4 | 1 |
+------+-------+
| 5 | 0 |
+------+-------+
I want to obtain the most repeated value for each name in part.
name 5 have the most repeated value 0
name 4 have the most repeated value 1
name 3 have the most repeated value 1
How can i do that in a single query to mysql ?
Thanks
SOLVED
With the select statement from #nvidot and another posts from SO, i found this is a common problem with this type of query.
Newer versions of MySQL come with ONLY_FULL_GROUP_BY enabled by default, and many of the solutions here will fail in testing with this condition.
So the working formula for me was:
SELECT DISTINCT t1.name, MAX(t1.occ), MAX(t2.value)
FROM (select name, value, count(*) as occ from `table` group by name, value order by occ desc) AS t1
JOIN (select name, adstatus, count(*) as occ from `table` group by name, value order by occ desc) AS t2 ON t2.name = t1.name AND t2.occ = (
SELECT MAX(occ) FROM (select name, value, count(*) as occ from `table` group by name, value order by occ desc) t3 WHERE t3.name = t1.name
)
GROUP BY t1.name;
In Oracle's PL/Sql, there is a specific feature can satisfy your request which is called Window function, but in MySql, there is no such thing untile mysql-8.0
SELECT `column`,
COUNT(`column`) AS `value_occurrence`
FROM `my_table`
GROUP BY `column`
ORDER BY `value_occurrence` DESC
Also please visit this link to more clear.
select name, val
from (select name, val, max(occ)
from (select name, val, count(*) as occ
from `sample` group by name, val
order by occ desc) as groups
group by name) as maximums;
Outer most select serves as cosmetic to display only name and val
order by occ desc serves to obtain the correct val
The following might be sufficient:
select name, val
from (select name, val, count(*) as occ
from `sample`
group by name, val
order by occ desc) as groups
group by name;
[edit]: The following should not trigger error as it does not use non-aggregate column and it does not rely on order by. Multiple name rows might exists if there exists multiples maxs for name/val count.
select name,val
from (select name as maxname, max(occ) as maxocc
from (select name, val, count(*) as occ
from `sample`
group by name, val) as counts2
group by name) as maxs
join (select name, val, count(*) as numocc
from `sample`
group by name, val) as counts1
on name = maxname AND numocc = maxocc;
I have two mysql tables with part numbers and qty's. I want to sum each tables qty sum(qty) ... group by partNumber Then join the two tables on the part number.
Sometimes table A will have part numbers that table b does not and vice versa. Below is an image of what I am expecting.
I've tried something like this, but this returns a row for each table and I want it to return 1 combined row
SELECT *, null as macroQty, sum(qty) as cardinalQty
FROM parts.cardinal where fileinfoid IN
(select cardinalFiles from parts.reports where fileinfoid = 418)
GROUP BY partNumber UNION ALL
SELECT *, sum(qty) as macroQty, null as cardinalQty
FROM parts.macro where fileinfoid IN
(select macroFiles from parts.reports where fileinfoid = 418 )
GROUP BY partNumber
I also tried wrapping it in an outer select and grouping by the part number from the outer select like this, but this results in the second inner select being null always
SELECT * FROM (
SELECT *, null as macroQty, sum(qty) as cardinalQty
FROM parts.cardinal where fileinfoid IN
(select cardinalFiles from parts.reports where fileinfoid = 418)
GROUP BY partNumber UNION ALL
SELECT *, sum(qty) as macroQty, null as cardinalQty
FROM parts.macro where fileinfoid IN
(select macroFiles from parts.reports where fileinfoid = 418 )
GROUP BY partNumber
) combined GROUP BY combined.partNumber
One approach would be to identify unique part numbers across the 2 tables (using a UNION with it's applied distinct) and then use correlated sub queries to get the sums. For example
drop table if exists a,b;
create table a(id int,val int);
create table b(id int,val int);
insert into a values(1,10),(1,10),(3,10),(4,10);
insert into b values (2,10),(4,10),(4,10);
select (select sum(a.val) from a where a.id = s.id) aval,
(select sum(b.val) from b where b.id = s.id) bval,
s.id partno
from
(
select id from a
union select id from b
) s
order by s.id;
+------+------+--------+
| aval | bval | partno |
+------+------+--------+
| 20 | NULL | 1 |
| NULL | 10 | 2 |
| 10 | NULL | 3 |
| 10 | 20 | 4 |
+------+------+--------+
4 rows in set (0.00 sec)
I would phrase this as a join between two subqueries which each find the sum in their respective tables. However, since each table does not necessarily contain all part numbers, and in fact there may be part numbers unique to each table, we will have to use a full outer join approach.
SELECT
t1.partNumber,
t1.cardinalQty,
COALECSE(t2.macroQty, 0) AS macroQty
FROM
(
SELECT partNumber, SUM(qty) AS cardinalQty
FROM cardinal
GROUP BY partNumber
) t1
LEFT JOIN
(
SELECT partNumber, SUM(qty) AS macroQty
FROM macro
GROUP BY partNumber
) t2
ON t1.partNumber = t2.partNumber
UNION ALL
SELECT
t2.partNumber,
0 AS cardinalQty,
t2.macroQty
FROM
(
SELECT partNumber, SUM(qty) AS cardinalQty
FROM cardinal
GROUP BY partNumber
) t1
RIGHT JOIN
(
SELECT partNumber, SUM(qty) AS macroQty
FROM macro
GROUP BY partNumber
) t2
ON t1.partNumber = t2.partNumber
WHERE t1.partNumber IS NULL;
Keep in mind that under normal conditions, in a well designed database, you should rarely encounter a situation which requires using a full outer join. Actually, a full outer join screams out that there is a design problem. In this case, you don't have a single parts table containing all part numbers. That table should exist, so unless you enjoy big ugly queries, you should create a parts table where the partNumber is a primary key.
I have a table like this:
name |id | state
name1 12 4
name1 12 4
name2 33 3
name2 33 4
...
I want to select every name and id from table where state is only 4, that means name1 is correct, because it only has two records with state 4 and nothing more. Meanwhile name2 is wrong, because it has record with state 4 and record with state 3.
You can use aggregation as shown below:
SELECT name, id
FROM your_table
GROUP BY name, id
HAVING SUM(state<>4)=0;
See a Demo on SQL Fiddle.
select name, id from mytable where id not in
(select distinct id from mytable where state <> 4)
you might need 2 sub queries .
select with group by name were state 4
select with group by name
compare the count if the count is same then select it
example : select name , count (name) from table where state = 4 as T1
select name , count (name) from table as T2
select T1.name from T1 and T2 where T2.count = T1.count
You can use not exists like this:
select distinct name, id
from table1 a
where not exists (select *
from table1 b
where a.id=b.id and state<>4)
In a more general case you can use count distinct (with not exists or with a join):
select distinct name, id
from table1 a
where not exists (
select *
from table1 b
where a.id=b.id
group by id
HAVING count(distinct state)>1)
I have student table
id | name | zip
1 | abc | 1234
2 | xyz | 4321
3 | cde | 1234
And i want to only display unique zip code which is 4321. I don't want to display the 1 and 3 record number. So, how can i display the unique record only?
Thanks In Advance.
The following query will give you all zip codes which don't appear in duplicate:
SELECT zip
FROM yourTable
GROUP BY zip
HAVING COUNT(*) = 1
If you want to also get the full records then you can use the above as a subquery to filter the original table:
SELECT *
FROM yourTable t1
INNER JOIN
(
SELECT zip
FROM yourTable
GROUP BY zip
HAVING COUNT(*) = 1
) t2
ON t1.zip = t2.zip
or this:
SELECT *
FROM yourTable
WHERE zip IN
(
SELECT zip
FROM yourTable
GROUP BY zip
HAVING COUNT(*) = 1
)
This will also work
select
id, name, zip
from
(select
id, name, zip, count(zip) as countZip
from
student
group by zip) as subq
where
countZip = '1'
There is a DISTINCT modifier that forces a select to show only one value for a column that may appear several times. In your case it would be:
SELECT DISTINCT ZIP
FROM ...
I have one table with two columns like this
Column1| Column2
A | A
B | C
D | D
The out put of the query as i expect is :
Name | Count
A | 2
B | 1
C | 1
D | 2
It is easy to sum two(values) but how do i concatenate nonvalues inside a table.
The query i tried:
select Column1 as Name from table union all select Column2 as Name from Table
I get the combined version of two columns but how am i suuposed to get the count(Name) ?
This will work perfectly..
SELECT t.Name, COUNT(t.Name) AS Count
FROM (
select `Column1` as Name from table
union all
select `Column2` as Name from table
) t
GROUP BY t.Name
Try this
Select Name, Count = count(*)
from (Select Name = column1 from table union all select column2 from table)t
group by Name
I think these SQl will help you.
select * from (
select column1 as col,count(Column1) as count from table_1 GROUP BY col
union all
select column2 as col, count(Column2) as count from table_1 GROUP BY col ) as table_alias group by col
Thank you.