I have a MySQL table with position key (65,000 records). I deleted, updated some rows in the middle of the table. Now I have, for example, something like this in the position 1 - 6 - 2 - 9
id
category
position
1
1
1
2
1
6
3
2
2
4
2
9
I want to reset / reorder the position key
id
category
position
1
1
1
2
1
2
3
2
1
4
2
2
How can I reset position where category = 1
and where category = 2?
Try this:
UPDATE source_table
JOIN ( SELECT id, ROW_NUMBER() OVER (PARTITION BY category ORDER BY position) position
FROM source_table ) subquery USING (id)
SET source_table.position = subquery.position
mysql> SHOW VARIABLES LIKE "%version%"; 5.7.24 – sagittarius
UPDATE source_table
JOIN ( SELECT t1.id, COUNT(t2.id) position
FROM source_table t1
JOIN source_table t2 ON t1.category = t2.category
AND t1.position >= t2.position
GROUP BY t1.id ) subquery USING (id)
SET source_table.position = subquery.position;
fiddle
if position is duplicated everything crashes – sagittarius
UPDATE source_table
JOIN ( SELECT t1.id, COUNT(t2.id) position
FROM source_table t1
JOIN source_table t2 ON t1.category = t2.category
AND ( t1.position > t2.position
OR ( t1.position = t2.position
AND t1.id >= t2.id ))
GROUP BY t1.id ) subquery USING (id)
SET source_table.position = subquery.position;
fiddle
UPDATE source_table t1
INNER JOIN
(
SELECT id,category,position, ROW_NUMBER() OVER (PARTITION BY category
ORDER BY position) position2
FROM source_table
) t2
ON t2.id = t1.id
SET
t1.position = t2.position2
I think this code is easy to understand and apply.
Related
I like to add event duration to a previous record every time a new record gets added.
This is what I have
ID EventType EventTime EventDuration
-------------------------------------
1 TypeA 10:20 NULL
2 TypeB 09:30 NULL
3 TypeC 08:00 NULL
This is what I want to achieve:
ID EventType EventTime EventDuration
-------------------------------------
1 TypeA 10:20 00:50
2 TypeB 09:30 01:30
3 TypeC 08:00 ...
4 ... ...
When a new records gets added (with ID, EventType and EventTime), the duration of the previous record (timediff between TypeB and Type A) should be added to the previous record in column EventDuration.
What I have so far is:
SELECT
id, EventTime,
timestampdiff(minute,
(SELECT EventTime
FROM TableName t2
WHERE t2.id < t1.id ORDER BY t2.id DESC LIMIT 1),EventTime)
AS EventDuration
FROM records t1
WHERE id = ....<this is where I get stuck, this should be a query that identifies the ID of latest EventTime record>
Any suggestions?
(I am running MySQL 5.6.39)
If you are running MySQL 8.0, you can use window functions for this:
update mytable t
inner join (
select id, timediff(eventTime, lag(eventTime) over(order by eventTime)) event_duration
from mytable t
) t1 on t1.id = t.id
set t.event_duration = t1.event_duration
If you want to update only the last but 1 record, you can order by and limit in the subquery (or in the outer query):
update mytable t
inner join (
select id, timediff(eventTime, lag(eventTime) over(order by eventTime)) event_duration
from mytable t
order by id desc
limit 1, 1
) t1 on t1.id = t.id
set t.event_duration = t1.event_duration
In earlier versions, one option is to emulate lag() with a window function:
update mytable t
inner join (
select
id,
timediff(
(select min(eventTime) from mytable t1 where t1.eventTime > t.eventTime),
eventTime
) event_duration
from mytable t
) t1 on t1.id = t.id
set t.event_duration = t1.event_duration
I want a sql query to get the row of products with a minimum price and get all of other fields of two table.
Consider this table:
T1: T2:
id Title id pcount price t1_id(foreign key)
1 x 1 3 3000 2
2 y 2 8 2500 2
3 z 3 4 1200 1
4 6 1000 1
5 9 4000 3
How can I select the below columns that have the minimum value in the price column, grouped by Title and get below fields? Like this:
id Title pcount price t1_id
1 y 8 2500 2
2 x 6 1000 1
3 z 9 4000 3
For Sql Server you can use OUTER APPLY:
select * from t1
outer apply(select top 1 * from t2 where t1_id = t1.id order by price) oa
Try like this,
SELECT t1.*,
t3.*
FROM T1 t1
CROSS apply (SELECT Min(price) AS price
FROM T2
WHERE t1_id = t1.tableid)t2
LEFT OUTER JOIN t2 t3
ON t3.t1_id = t1.tableid
AND t3.price = t2.price
select *
from t1
left join
(select pcount, price, t2.t1_id
from t2
join
(select t1_id, min(price) pmin
from t2
group by t1_id
) tt
where t2.t1_id = tt.t1_id and price = pmin
) tt1
on t1.id = tt1.t1_id
result
id Title pcount price t1_id
1 x 6 1000 1
2 y 8 2500 2
3 z 9 4000 3
Also check this :
declare #t1 table(id int , title varchar(50))
declare #t2 table(id int , pcount int, price int, t1_id int)
insert into #t1 values (1, 'x' ), (2,'y'), (3,'z')
insert into #t2 values (1, 3, 3000, 2 ), (2, 8, 2500, 2 ),(3, 4, 1200, 1 ),(4, 6, 1000, 1),(5, 9, 4000, 3)
;with cte
as(
select * from (select * , ROW_NUMBER() OVER (PARTITION BY t1_id ORDER BY t1_id asc, price asc ) AS sequence_id from #t2 ) a where sequence_id = 1
)
select t1.*, cte.pcount ,cte.price from #t1 t1 join cte on t1.id = cte.t1_id
--or understand more
;with cte as
(
select t1_id, min(price) price
from #t2 group by t1_id
)
, cte1 as
(
select t1.*,t2.pcount, cte.* from #t1 t1
left outer join #t2 t2 on t1.id = t2.t1_id
left outer join cte cte on t1.id = cte.t1_id and (t2.t1_id =cte.t1_id and t2.price = cte.price)
)
select * from cte1 where t1_id is not null
Please Suggest to get single 0 type row from multiple (0 type rows) and selected row should be just before type 1 row
Emp_tbl (id,type,company_id,created_at)
1,0,121,2015-02-19 18:05
2,0,121,2015-02-19 18:15
3,0,121,2015-02-19 18:17
4,1,121,2015-02-19 19:22
5,2,121,2015-02-19 19:25
6,0,121,2015-02-19 22:05
7,0,121,2015-02-19 22:15
8,0,121,2015-02-19 22:17
9,1,121,2015-02-19 22:22
10,2,121,2015-02-19 22:25
Expected Result
3,0,121,2015-02-19 18:17
4,1,121,2015-02-19 19:22
5,2,121,2015-02-19 19:25
8,0,121,2015-02-19 22:17
9,1,121,2015-02-19 22:22
10,2,121,2015-02-19 22:25
So what you want is the MAX(Id) of the type = 0 rows for each row that has type = 1, where the Id is less. You can join and group to get that:
select max(t0.Id) Id
from Emp_tbl t1
join Emp_tbl t0 on t0.type = 0 and t0.Id < t1.Id
where t1.type = 1
group by t1.Id
The rest is just putting it together:
select *
from Emp_tbl
where type <> 0
union all
select t.*
from Emp_tbl t
join (
select max(t0.Id) Id
from Emp_tbl t1
join Emp_tbl t0 on t0.type = 0 and t0.Id < t1.Id
where t1.type = 1
group by t1.Id
) t0 on t.Id = t0.Id
SQL Fiddle demo
I have this table e.g.:
Id StatusDate Status
1 20-08-2014
1 15-08-2014
1 09-08-2014 P
2 17-08-2014
1 10-08-2014
2 12-08-2014
2 06-07-2014 P
1 30-07-2014
2 02-07-2014
2 01-07-2014 P
...... and so on
I want to select count by ID where status is blank until I hit the first 'P' in ascending order of date group by ID. So my results will be like this.
ID Count
1 3
2 2
Try it out. Not tested
SELECT t1.ID, count(*) FROM table t1
WHERE t1.StatusDate >= (SELECT MAX(t2.StatusDate) FROM table t2
WHERE t1.ID = t2.ID AND t2.Status = 'P')
GROUP BY t1.ID
Assuming your table name is StatusTable This will work:
SELECT
ID,
COUNT(*) AS `Count`
FROM StatusTable AS st
WHERE
st.Status = ''
AND st.StatusDate > (
SELECT st2.StatusDate
FROM `StatusTable` AS st2
WHERE st.ID = st2.ID
AND st2.Status = 'P'
ORDER BY st2.StatusDate DESC
LIMIT 1
)
GROUP BY st.ID
ORDER BY st.ID
One option is to use a JOIN and COUNT rows which have a lower statusdate value, like this:
SELECT t1.id, SUM(CASE WHEN t1.statusdate > t2.statusdate THEN 1 ELSE 0 END) AS mycount
FROM t t1 JOIN (
SELECT id, MIN(statusdate) statusdate
FROM t
WHERE status = 'P'
GROUP BY id
) t2
ON t1.id = t2.id
GROUP BY t1.id
Working Demo: http://sqlfiddle.com/#!2/d9d91/2
I have this table where I only want to look at AB
ID CODE COUNT
102 AB 9
101 AB 8
100 AC 23 //not important!!!!
99 AB 7
98 AB 6
97 AB 5
96 AB 0
Conversed to this
ID NEWID CODE COUNT
102 102 AB 9
101 101 AB 8
99 100 AB 7
98 99 AB 6
97 98 AB 5
96 97 AB 0
Using this query:
SELECT t.ID, #NEWID := COALESCE(#NEWID - 1, t.ID) AS NEWID, t.CODE, t.COUNT
FROM
(SELECT ID, CODE, COUNT FROM some_table WHERE CODE = 'AB' ORDER BY ID DESC) t,
(SELECT #NEWID := NULL) _uv;
http://sqlfiddle.com/#!2/e0b8b/1/0
And now I want to count the difference of each consecutive NEWID.
So
Step 1: 9 - 8 = 1
Step 2: 8 - 7 = 1
Step 3: 7 - 6 = 1
Step 4: 6 - 5 = 1
Step 5: 5 - 0 = 5
I'm used to doing this with
LEFT OUTER JOIN some_table t2 ON t.ID = ( t2.ID + 1 )
And then taking the difference between t2.count and t.count,
but now when I'm using COALESCE, I cannot select this NEWID, so the code below does not work.
LEFT OUTER JOIN some_table t2 ON t.NEWID = ( t2.NEWID + 1 )
So how should I resolve this issue?
Oh, so that's why you needed sequential IDs. Well, you can use user variables for this, too, and you don't even need NEWID! Since you're doing stuff like this, you'd do well to read up on how user variables work.
SELECT
t.ID, t.CODE, t.COUNT,
#PREVCOUNT - t.COUNT DIFFERENCE,
#PREVCOUNT := t.COUNT -- Updates for the next iteration, so it
-- must come last!
FROM
(SELECT ID, CODE, COUNT FROM some_table WHERE CODE = 'AB' ORDER BY ID DESC) t,
(SELECT #PREVCOUNT := NULL) _uv;
SQL Fiddle
Try this:
SELECT
t1.ID as ID1,
t2.ID as ID2,
t1.CODE as CODE,
t1.COUNT as C1,
t2.COUNT as C2,
t2.COUNT - t1.COUNT as DIFF
FROM
some_table t1
INNER JOIN some_table t2 ON t1.ID < t2.ID AND t1.CODE = t2.CODE
WHERE
t1.CODE='AB'
AND NOT EXISTS
(SELECT * FROM some_table t3
INNER JOIN some_table t4 ON t3.ID < t4.ID and t3.CODE = t4.CODE
WHERE
t3.CODE='AB'
AND t1.ID = t3.ID
AND t4.ID < t2.ID
)
ORDER BY t1.ID
Another way will be to use LIMIT:
SELECT
t.ID1 AS ID,
t.CODE as CODE,
t.C2-t.C1 AS DIFF
FROM
(
SELECT
t1.ID as ID1,
t1.CODE as CODE,
t1.COUNT as C1,
(SELECT t.COUNT
FROM some_table t
WHERE t.ID > t1.ID AND t.CODE=t1.CODE
ORDER BY t.ID
LIMIT 1) as C2
FROM
some_table t1
WHERE
t1.CODE='AB'
ORDER BY t1.ID) t
ORDER BY t.ID1
http://sqlfiddle.com/#!2/e0b8b/24