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How can I return pivot table output in MySQL?
(10 answers)
MySQL - Rows to Columns
(13 answers)
Closed last month.
if have 2 tables:
tool_id
name
status
1
Mike
1
1
Claus
3
1
Max
3
2
Mike
2
2
Claus
2
3
Mike
1
3
Claus
3
3
Max
1
3
Sam
1
4
Mike
2
and
tool_id
tool_name
1
51363
2
52514
3
51458
4
51608
I need a view that shows me these 2 tables as a matrix. The tools should be displayed in the table headers and the names and their status for the corresponding tool as a table.
If a name is not assigned to a tool, it should be given a zero.
name
51363
52514
51458
51608
Mike
1
2
1
2
Claus
3
2
3
0
Max
3
0
3
0
Sam
0
0
1
0
I have more than 400 tools and workers each in the two tables.
Is something like this possible?
Edit: This is not an duplicate of the linked posts.
I need a dynamic creation of columns.
I have a 2 Mysql tables like 1.Product(This table is hierarchical or recursive) and 2.Sales table in this will store sale id and product id. I need to show parent product with the sum of all hierarchical child product.
Product table having data like,
id name parent_id
1 Necklace NULL
2 Ring NULL
3 Earing NULL
4 Choker 1
5 Long Necklace 1
6 Short Necklace 1
7 2-Line 5
8 3-Line 5
9 Mango 5
10 Green 7
11 Red 7
12 White 7
13 Stud 3
Sales table will have data like,
id product_id no_of_pcs weight rate
1 10 5 40 35000
2 12 8 50 50000
3 9 2 20 25000
4 6 1 8 25000
5 13 2 16 22000
Now I'm trying the result as,
Product sale_pcs tot_pcs sale_wt sale_rate
1 Necklace 16 118 135000
3 Earing 2 16 22000
Now I'm using mysql query inside php recursive function by using product table. By using this even recursive function all the products need to check with sales table. This will happening performance issue. Could you please help any one to solve this issue whether this possible by doing in query itself
I have a linking table in MySQL which has the id's of people in one column and the id's of media that they have appeared in.
I have run a query:
SELECT person_id,COUNT(*)
FROM person_media
GROUP BY person_id;
This has returned:
person_id COUNT(*)
1 7
2 4
3 9
4 5
5 9
6 12
7 12
8 3
9 1
10 8
11 8
12 9
13 3
14 1
15 4
16 3
17 3
18 1
19 8
20 1
21 4
What I am looking to do is to count how many people have a COUNT(*) of 4 or more. I can't seem to find a way to do it, but I know it has to be possible. I'm relatively new to MySQL, so be gentle :)
Just use HAVING
SELECT person_id,COUNT(*)
FROM person_media
GROUP BY person_id
HAVING COUNT(*)>=4
The inner query gets all those with a count of 4 and more.
The outer query counts how many that are:
select count(*)
from
(
SELECT 1
FROM person_media
GROUP BY person_id
HAVING count(*) >= 4
) tmp
I have a table that that is being joined by another table that looks like this:
Id Score Total
1 10 30
1 7 30
1 13 30
2 14 27
2 10 27
2 3 27
I want to be able to display this data like this in SSRS:
Id 1 2 3 Total
1 10 7 13 30
2 14 10 3 27
Can this be done and how?
You can do this by using a matrix.
You can add a row identifier for each id in your dataset (assuming you can modify the dataset, as you joined 2 tables). Below code is for SQL Server (T-SQL).
Select Id, Score, row_number() over (partition by id order by score) ident
from table
Output:
Id Score Ident
1 10 1
1 7 2
1 13 3
2 14 1
2 10 2
2 3 3
No need of the Total field, you can add it in matrix (Right Click on ColumnGroup>Add Total>After).
Use the above query in Matrix as shown below.
I’m trying to figure out how to count the values in more than one column.
It seem the first COUNT I do gives me the correct results but everything I’ve tried to get the second column count gives the wrong result.
For example, with the following two columns,
Q2 Q3
1 1
1 1
2 2
1 1
1 1
5 5
3 5
5 3
4 1
2 2
3 3
3 3
5 5
3 3
2 1
2 1
3 2
4 1
1 1
1 1
2 2
5 5
3 3
2 1
3 3
1 1
2 1
SELECT COUNT(Q2) AS QU2 FROM mytable GROUP BY Q2
QU2 = 7 7 7 2 4
gives me the count for Q2. 7 one’s, 7 two’s and so on...
However, the following gives me an unexpected result.
SELECT COUNT(Q2) AS QU2, COUNT(Q3) AS QU3 FROM mytable GROUP BY Q2, Q3
7 4 3 1 5 1 2 1 3
I think its something with the GROUP BY but I don’t know how to get around it to get the needed result.
So I'm tying to get the result of
QU2 = 7 7 7 2 4
QU3 = 13 4 6 4
Or
QU2 QU3
7 13
7 4
7 6
2 4
4
and so on for QU4 QU5 ... I would appreciate any help.
Thank you
I think that this will get you closest to what you want. You can replace the numbers table with any method that generates the numbers 1 to whatever the max value is in Q2 or Q3.
CREATE TABLE dbo.Numbers (num INT)
INSERT INTO dbo.Numbers (num) VALUES (1), (2), (3), (4), (5)
SELECT
N.num,
SUM(CASE WHEN MT.Q2 = N.num THEN 1 ELSE 0 END) AS QU2,
SUM(CASE WHEN MT.Q3 = N.num THEN 1 ELSE 0 END) AS QU3
FROM
dbo.Numbers N
CROSS JOIN dbo.My_Table MT
GROUP BY
N.num
Adding additional columns (for Q4, etc.) just means adding another SUM(CASE...)
How GROUP BY works?
Let's talk about your first query (I added the column Q2 in the SELECT clause to make its output more clear):
SELECT Q2, COUNT(*) AS QU2
FROM mytable
GROUP BY Q2
First, it gets all the rows matching the WHERE criteria, if a WHERE clause exists. Because your query doesn't have a WHERE clause, all the rows from the table are read.
On the next step the rows read on the previous step are grouped by the expression specified in the GROUP BY clause (let's assume it contains only one expression, as the query above does). Internally, grouping the rows requires sorting them first.
This is how the data is organized on this step. I added horizontal separators between the rows that go in each group to make everything clear:
Q2 Q3
-------
1 1
1 1
1 1
1 1
1 1
1 1
1 1
-------
2 1
2 1
2 1
2 1
2 2
2 2
2 2
-------
3 2
3 3
3 3
3 3
3 3
3 3
3 5
-------
4 1
4 1
-------
5 3
5 5
5 5
5 5
-------
On the next step, from each group it creates a single row that goes to the generated result set.
The query above clearly returns:
Q2 QU2
--------
1 7
2 7
3 7
4 2
5 4
What happens when the GROUP BY clause contains more than one expression?
Let's take your second query (again, I added some columns to show its behaviour):
SELECT Q2, Q3, COUNT(*) AS cnt
FROM mytable
GROUP BY Q2, Q3
It works similar with the previous query but, because the GROUP BY clause contains two expression, each group created for the values of Q2 is split in sub-groups based on the value of Q3. Assuming there is another expression (let' say, Q4) in the GROUP BY clause, each sub-group created for a pair (Q2, Q3) is further divided into sub-groups for all the values of Q4 and so on.
For your table, the groups and sub-groups are as follows:
Q2 Q3
=======
1 1
1 1
1 1
1 1
1 1
1 1
1 1
=======
2 1
2 1
2 1
2 1
---
2 2
2 2
2 2
=======
3 2
---
3 3
3 3
3 3
3 3
3 3
---
3 5
=======
4 1
4 1
=======
5 3
---
5 5
5 5
5 5
=======
I used double lines to separate the groups and smaller single lines to separate the subgroups inside each group.
The output of this query is:
Q2 Q3 cnt
------------
1 1 7
2 1 4
2 2 3
3 2 1
3 3 5
3 5 1
4 1 2
5 3 1
5 5 3
How to get the desired result?
It is not possible to get the result you want using a single query. Even more, the result sets you suggest doesn't make much sense.
You can combine two queries using UNION in order to get the data you need and additional information that helps you know where those numbers come from:
SELECT 'Q2' AS source, Q2 AS q, COUNT(Q2) AS cnt FROM mytable GROUP BY Q2
UNION
SELECT 'Q3' AS source, Q3 AS q, COUNT(Q3) AS cnt FROM mytable GROUP BY Q3
The output is:
source q cnt
----------------
Q2 1 7
Q2 2 7
Q2 3 7
Q2 4 2
Q2 5 4
Q3 1 13
Q3 2 4
Q3 3 6
Q3 5 4
Pretty clear, isn't it? The first 5 rows come from the query GROUP BY Q2 and their value in the column q tells what was the value of Q2 for each group (there are 7 occurrences of 1 in column Q2, 7 of 2, 7 of 3, 2 of 4 and so on). The last 4 rows tell the similar story about Q3 (13 rows have 1 in column Q3 and so on).
Remark
There is a difference between COUNT(*) and COUNT(Q2): COUNT(*) counts the rows from the group, COUNT(Q2) counts the not-NULL values in the column Q2. It doesn't care about duplicate, it only ignore the NULL values. If you want to count the distinct values then you have to add the DISTINCT keyword: COUNT(DISTINCT Q2).
I think you need to unpivot the data. In this case, that just means multiple group by connected by union all:
select 'q2' as which, q2, count(*) as cnt
from mytable
group by q2
union all
select 'q3' as which, q3, count(*) as cnt
from mytable
group by q3;
You can add as many more subqueries as you like.
Note: this puts the values in separate rows, rather than in separate columns.
I reckon Asaph is on the right track , however I would alter this slightly try select distinct count(Q2) as QU2, count(Q3) as QU3 from myTable;