MySQL Get rows that do not match with certain conditions - mysql

It seems simple in my head but I am at a loss for getting the results I need.
My table
id, code, type
1 1111 1
2 1111 2
3 1222 1 <--- This one
4 1333 1
5 1333 2
6 1444 3 <--- Different type then the others
I want the output of the one that doesn't have a matching code with type 2 but only look for ones with type 1 or type 2 (if that makes sense)
id, code, type
3 1222 1
NOTE: I have over 1 million records to query so I need something fast.
My SqlFiddle
Thanks in advance.

SELECT * FROM codes NATURAL JOIN (
SELECT code
FROM codes
WHERE type IN (1,2)
GROUP BY code
HAVING COUNT(DISTINCT type) = 1
) t
See it on sqlfiddle.

Here is a solution using not exists:
SELECT c.*
FROM codes c
WHERE c.type = 1 and
not exists (select 1
from codes c2
where c2.code = c.code and
c2.type = 2
)

Related

Compare 2 views with different number of columns

I have 2 views with different number of columns. 1 of the views has been joined with another view that is why it has additional columns.
The first view has 113 records (View 2), while the updated view (View 1) has 130 columns. I would like to find out the number of records that are extra in View 1
.
View 1 View 2
A|B|C|D|E A|B|C
1 2 3 4 5 1 2 3
1 2 3 7 8
3 2 1 4 5 3 2 1
3 2 1 7 8
expected result :
1 2 3 7 8
3 2 1 7 8
Thanks.
You can get that extra records by using 'not in' or 'not exists' conditions
select * from view1 m where not exists (
select 1 from view2 u where (m.a=u.a and m.b=u.b and m.c=u.c)
You can change those conditions as per your requirement
With left join also will get the required result
select m.* from view1 m left join view2 u
(m.a=u.a and m.b=u.b and m.c=u.c)
where u.a is null and u.b is null and u.c is null
You shoul probably refactor your DB schema and data logic.
But just to resolve your weird requirements you can:
http://sqlfiddle.com/#!9/cf2c50/2
SELECT t.a, t.b, t.c, t.d, t.e
FROM (
SELECT v1.*, IF(#idx = concat(v1.a,v1.b,v1.c),1,0) `filter`,#idx := concat(v1.a,v1.b,v1.c)
FROM v1
INNER JOIN v2
ON v1.a=v2.a AND v1.b=v2.b AND v1.c=v2.c
ORDER BY v1.a,v1.b,v1.c
) t
WHERE t.`filter`=1;
It is not best example of query performance, but it should return expected result.

MySQL Group by week num w/ multiple date column

I have a table with columns similar to below , but with about 30 date columns and 500+ records
id | forcast_date | actual_date
1 10/01/2013 12/01/2013
2 03/01/2013 06/01/2013
3 05/01/2013 05/01/2013
4 10/01/2013 09/01/2013
and what I need to do is get a query with output similar to
week_no | count_forcast | count_actual
1 4 6
2 5 7
3 2 1
etc
My query is
SELECT weekofyear(forcast_date) as week_num,
COUNT(forcast_date) AS count_forcast ,
COUNT(actual_date) AS count_actual
FROM
table
GROUP BY
week_num
but what I am getting is the forcast_date counts repeated in each column, i.e.
week_no | count_forcast | count_actual
1 4 4
2 5 5
3 2 2
Can any one please tell me the best way to formulate the query to get what I need??
Thanks
try:
SELECT weekofyear(forcast_date) AS week_forcast,
COUNT(forcast_date) AS count_forcast, t2.count_actual
FROM
t t1 LEFT JOIN (
SELECT weekofyear(actual_date) AS week_actual,
COUNT(forcast_date) AS count_actual
FROM t
GROUP BY weekOfYear(actual_date)
) AS t2 ON weekofyear(forcast_date)=week_actual
GROUP BY
weekofyear(forcast_date), t2.count_actual
sqlFiddle
You have to write about 30 (your date columns) left join, and the requirement is that your first date column shouldn'd have empty week (with a count of 0) or the joins will miss.
Try:
SELECT WeekInYear, ForecastCount, ActualCount
FROM ( SELECT A.WeekInYear, A.ForecastCount, B.ActualCount FROM (
SELECT weekofyear(forecast_date) as WeekInYear,
COUNT(forecast_date) as ForecastCount, 0 as ActualCount
FROM TableWeeks
GROUP BY weekofyear(forecast_date)
) A
INNER JOIN
( SELECT * FROM
(
SELECT weekofyear(forecast_date) as WeekInYear,
0 as ForecastCount, COUNT(actual_date) as ActualCount
FROM TableWeeks
GROUP BY weekofyear(actual_date)
) ActualTable ) B
ON A.WeekInYear = B.WeekInYear)
AllTable
GROUP BY WeekInYear;
Here's my Fiddle Demo
Just in case someone else comes along with the same question:
Instead of trying to use some amazing query, I ended up creating an array of date_columns_names and a loop in the program that was calling this query, and for each date_column_name, performing teh asme query. It is a bit slower, but it does work

MySQL: Another max per group? Two tables

My database tracks sections users have completed:
Table 'users':
id user_id sections_id
//
4 46 1
5 46 2
6 46 4
7 46 5
//
Table 'sections':
id header_id name
1 1 1/3
2 1 2/3
3 1 3/3
4 2 1/3
5 2 2/3
6 2 3/3
The following query
SELECT a.sections_id
,b.header_id
FROM users a
JOIN sections b
ON a.sections_id = b.id
WHERE a.user_id = 46;
// a.user_id can be just user_id, but added for clarity
Gives me:
sections_id header_id
1 1
2 1
4 2
5 2
What I want is max section ID per header for a particular user, so that I know which section I need to serve the user:
sections_id header_id
2 1
5 2
I'm assuming this is a max per group problem, but I can't quite get my head around the solution. I could throw all the data into my PHP and parse out from there, but it seems I should be able to do it via the SQL. TIA!
This is a simple group by query:
SELECT s.header_id, max(u.sections_id)
FROM users u JOIN
sections s
ON u.sections_id = s.id
WHERE u.user_id = 46
group by s.header_id;
I also changed your aliases to be the initials of the table. This makes the query much easier to follow.
Edit: SQLFiddle Here: http://sqlfiddle.com/#!2/dbb5a/2
You could add a group by clause with a max() function
SELECT max(a.sections_id)
,b.header_id
FROM users a
JOIN sections b
ON a.sections_id = b.id
WHERE a.user_id = 46
GROUP BY header_id;

Mysql Count per column

I have the following query:
SELECT a.feeder_id, b.feeder_pr
FROM authors_article_feeders a
LEFT JOIN feeders b ON b.id = a.feeder_id
WHERE website_id =1
LIMIT 0 , 30
which results in:
feeder_id feeder_pr
18 2
18 2
18 2
18 2
32 6
What I need is to modify the above query so that it will manipulate this data so that the result would end up with a count of each feeder_pr, so in this case the result would be:
feeder_pr count
2 4
6 1
Any assistance is appreciated. If you have time please describe your solution so that I can learn from it while I'm at it.
Everything I've tried has ended in inaccurate results, usually with just one row instead of the expected 2.
You just need to add a GROUP BY And, you would not even need the joins
SELECT b.feeder_pr, COUNT(b.feeder_pr)
FROM feeders b
GROUP BY b.feeder_pr
SELECT b.feeder_pr, count(a.feeder_id) as count
FROM authors_article_feeders a
LEFT JOIN feeders b ON b.id = a.feeder_id
WHERE website_id =1
GROUP BY 1

Using join in place of this sub-query in MySQL

I have a table by the following structure and records, All i want to do is to just extract orderid of those records whose status id is either 1 or 2 , i want to exclude all orderid with statusid=3 , , problem is that orderid 106 has both status 1 and 3 ...
I have written a sub-query which serves the purpose..
select *
from orders_status_history
where orders_id NOT IN
(select orders_id
from orders_status_history
where orders_status_id = 3)
is there any other way of doing this without using sub-queries as i have heard it hampers performance. As my query can return thousands of rows as well.
id order-id status-id
1 1 1
2 2 1
3 105 1
4 106 1
5 106 3
6 108 1
7 109 1
8 109 2
Any help or suggestion will be highly appreciated ..Thanks in advance..
You may do that:
SELECT osh.*
FROM orders_status_history osh
LEFT JOIN
orders_status_history oshd
ON oshd.orders_id = osh_orders_id
AND oshd.orders_status_id = 3
WHERE oshd.orders_id IS NULL
However, if you have an index on order_status_history (orders_id, orders_status_id), then the NOT IN query is just as fine.
You may want to read this:
NOT IN vs. NOT EXISTS vs. LEFT JOIN / IS NULL: MySQL
I wonder why you use sub query while you can use the following query
select orders_id from orders_status_history where orders_status_id <> 3
Please try this , and I hope it helps