I'm struggling emulating a lead function to calculate the difference of (after date - current date)
I'm currently using mysql 5.7 to accomplish this. I have tried looking at various sources on stack overflow but I'm not sure how to get the result.
This is what I want:
What I currently have now is the same thing without the days column.
I would also like to know how to get a column of dates that grabs the date after the current date.
This seems to work (except for the unclear row=4):
DROP TABLE IF EXISTS table4;
CREATE TABLE table4 (id integer, user_id integer, product varchar(10), `date` date);
INSERT INTO table4 VALUES
(1,1,'item1','2020-01-01'),
(2,1,'item2','2020-01-01'),
(3,1,'item3','2020-01-02'),
(4,1,'item4','2020-01-02'),
(5,2,'item5','2020-01-06'),
(6,2,'item6','2020-01-09'),
(7,2,'item7','2020-01-09'),
(8,2,'item8','2020-01-10');
SELECT
id,
user_id,
product,
date,
(SELECT date FROM table4 t4 WHERE t4.id>t1.id LIMIT 1) x,
COALESCE(DATEDIFF((SELECT date FROM table4 t4 WHERE t4.id>t1.id LIMIT 1),date),0) as days
FROM table4 t1
output:
+ ------- + ------------ + ------------ + --------- + ----------- + --------- +
| id | user_id | product | date | x | days |
+ ------- + ------------ + ------------ + --------- + ----------- + --------- +
| 1 | 1 | item1 | 2020-01-01 | 2020-01-01 | 0 |
| 2 | 1 | item2 | 2020-01-01 | 2020-01-02 | 1 |
| 3 | 1 | item3 | 2020-01-02 | 2020-01-02 | 0 |
| 4 | 1 | item4 | 2020-01-02 | 2020-01-06 | 4 |
| 5 | 2 | item5 | 2020-01-06 | 2020-01-09 | 3 |
| 6 | 2 | item6 | 2020-01-09 | 2020-01-09 | 0 |
| 7 | 2 | item7 | 2020-01-09 | 2020-01-10 | 1 |
| 8 | 2 | item8 | 2020-01-10 | | 0 |
+ ------- + ------------ + ------------ + ---------- + ---------- + --------- +
The column x is only here for to see which date is returned from the subquery, and not really needed for the final result.
DBFIDDLE
EDIT: when there are no "gaps" in the numbering of id, you could do this to get a solution which should have more performance:
SELECT
t1.id,
t1.user_id,
t1.product,
t1.date,
COALESCE(DATEDIFF(t2.date,t1.date),0) as days
FROM table4 t1
LEFT JOIN table4 t2 on t2.id = t1.id+1
I added this to the DBFIDDLE
I need to select first 2 lines where the store_name is different than one given for a given product
id | store_name | prod_name
----+------------+------
1 | 1 | A
2 | 1 | B
3 | 1 | C
4 | 1 | A
5 | 2 | E
6 | 2 | A
7 | 3 | G
8 | 2 | A
9 | 1 | A
10 | 3 | A
(10 rows)
result should be store_name <> 3 AND prod_name ='A'
id | store_name | prod_name
----+------------+------
1 | 1 | A
4 | 1 | A
6 | 2 | A
8 | 2 | A
Use the row_number() window function to accomplish this.
Query #1
with first_two as (
select *,
row_number() over (partition by store_name
order by id) as rn
from store_product
where store_name <> 3
and prod_name = 'A'
)
select id, store_name, prod_name
from first_two
where rn <= 2;
| id | store_name | prod_name |
| --- | ---------- | --------- |
| 1 | 1 | A |
| 4 | 1 | A |
| 6 | 2 | A |
| 8 | 2 | A |
View on DB Fiddle
TIL about tablefunc and crosstab. At first I wanted to "group data by columns" but that doesn't really mean anything.
My product sales look like this
product_id | units | date
-----------------------------------
10 | 1 | 1-1-2018
10 | 2 | 2-2-2018
11 | 3 | 1-1-2018
11 | 10 | 1-2-2018
12 | 1 | 2-1-2018
13 | 10 | 1-1-2018
13 | 10 | 2-2-2018
I would like to produce a table of products with months as columns
product_id | 01-01-2018 | 02-01-2018 | etc.
-----------------------------------
10 | 1 | 2
11 | 13 | 0
12 | 0 | 1
13 | 20 | 0
First I would group by month, then invert and group by product, but I cannot figure out how to do this.
After enabling the tablefunc extension,
SELECT product_id, coalesce("2018-1-1", 0) as "2018-1-1"
, coalesce("2018-2-1", 0) as "2018-2-1"
FROM crosstab(
$$SELECT product_id, date_trunc('month', date)::date as month, sum(units) as units
FROM test
GROUP BY product_id, month
ORDER BY 1$$
, $$VALUES ('2018-1-1'::date), ('2018-2-1')$$
) AS ct (product_id int, "2018-1-1" int, "2018-2-1" int);
yields
| product_id | 2018-1-1 | 2018-2-1 |
|------------+----------+----------|
| 10 | 1 | 2 |
| 11 | 13 | 0 |
| 12 | 0 | 1 |
| 13 | 10 | 10 |
I have this table named Samples. The Date column values are just symbolic date values.
+----+------------+-------+------+
| Id | Product_Id | Price | Date |
+----+------------+-------+------+
| 1 | 1 | 100 | 1 |
| 2 | 2 | 100 | 2 |
| 3 | 3 | 100 | 3 |
| 4 | 1 | 100 | 4 |
| 5 | 2 | 100 | 5 |
| 6 | 3 | 100 | 6 |
...
+----+------------+-------+------+
I want to group by product_id such that I have the 1'th sample in descending date order and a new colomn added with the Price of the 7'th sample row in each product group. If the 7'th row does not exist, then the value should be null.
Example:
+----+------------+-------+------+----------+
| Id | Product_Id | Price | Date | 7thPrice |
+----+------------+-------+------+----------+
| 4 | 1 | 100 | 4 | 120 |
| 5 | 2 | 100 | 5 | 100 |
| 6 | 3 | 100 | 6 | NULL |
+----+------------+-------+------+----------+
I belive I can achieve the table without the '7thPrice' with the following
SELECT * FROM (
SELECT ROW_NUMBER() OVER (PARTITION BY Product_Id ORDER BY date DESC) r, * FROM Samples
) T WHERE T.r = 1
Any suggestions?
You can try something like this. I used your query to create a CTE. Then joined rank1 to rank7.
;with sampleCTE
as
(SELECT ROW_NUMBER() OVER (PARTITION BY Product_Id ORDER BY date DESC) r, * FROM Samples)
select *
from
(select * from samplecte where r = 1) a
left join
(select * from samplecte where r=7) b
on a.product_id = b.product_id
I have a table like this
Event ID | Contract ID | Event date | Amount |
----------------------------------------------
1 | 1 | 2009-01-01 | 100 |
2 | 1 | 2009-01-02 | 20 |
3 | 1 | 2009-01-03 | 50 |
4 | 2 | 2009-01-01 | 80 |
5 | 2 | 2009-01-04 | 30 |
For each contract I need to fetch the latest event and amount associated with the event and get something like this
Event ID | Contract ID | Event date | Amount |
----------------------------------------------
3 | 1 | 2009-01-03 | 50 |
5 | 2 | 2009-01-04 | 30 |
I can't figure out how to group the data correctly. Any ideas?
Thanks in advance.
SQL 2k5/2k8:
with cte_ranked as (
select *
, row_number() over (
partition by ContractId order by EvantDate desc) as [rank]
from [table])
select *
from cte_ranked
where [rank] = 1;
SQL 2k:
select t.*
from table as t
join (
select max(EventDate) as MaxDate
, ContractId
from table
group by ContractId) as mt
on t.ContractId = mt.ContractId
and t.EventDate = mt.MaxDate