I need to set a sequence inside T-SQL when in the first column I have sequence marker (which is repeating) and use other column for ordering.
It is hard to explain so I try with example.
This is what I need:
|------------|-------------|----------------|
| Group Col | Order Col | Desired Result |
|------------|-------------|----------------|
| D | 1 | NULL |
| A | 2 | 1 |
| C | 3 | 1 |
| E | 4 | 1 |
| A | 5 | 2 |
| B | 6 | 2 |
| C | 7 | 2 |
| A | 8 | 3 |
| F | 9 | 3 |
| T | 10 | 3 |
| A | 11 | 4 |
| Y | 12 | 4 |
|------------|-------------|----------------|
So my marker is A (each time I met A I must start new group inside my result). All rows before first A must be set to NULL.
I know that I can achieve that with loop but it would be slow solution and I need to update a lot of rows (may be sometimes several thousand).
Is there a way to achive this without loop?
You can use window version of COUNT to get the desired result:
SELECT [Group Col], [Order Col],
COUNT(CASE WHEN [Group Col] = 'A' THEN 1 END)
OVER
(ORDER BY [Order Col]) AS [Desired Result]
FROM mytable
If you need all rows before first A set to NULL then use SUM instead of COUNT.
Demo here
Related
I have one table where I dump all records from different sources (x, y, z) like below
+----+------+--------+
| id | source |
+----+--------+
| 1 | x |
| 2 | y |
| 3 | x |
| 4 | x |
| 5 | y |
| 6 | z |
| 7 | z |
| 8 | x |
| 9 | z |
| 10 | z |
+----+--------+
Then I have one mapping table where I map values between sources based on my usecase like below
+----+-----------+
| id | mapped_id |
+----+-----------+
| 1 | 2 |
| 1 | 9 |
| 3 | 7 |
| 4 | 10 |
| 5 | 1 |
+----+-----------+
I want merged results where I can see only unique results like
+-----+------------+
| id | mapped_ids |
+-----+------------+
| 1 | 2,9,5 |
| 3 | 7 |
| 4 | 10 |
| 6 | null |
| 8 | null |
+-----+------------+
I am trying different options but could not figure this out, is there way I can write joins to do this. I have to use the mapping table where associations are stored and identify unique records along with records which are not mapped anywhere.
My understanding is, you want to see all dump_table IDs that do not appear in the mapping_id column and then aggregate the mapped_ids for those that are left:
select d1.id,
array_agg(m1.mapped_id order by m1.mapped_id) filter (where m1.mapped_id is not null) as mapped_ids
from dump_table d1
left join mapping_table m1 using (id)
where not exists (select *
from mapping_table m2
where m2.mapped_id = d1.id)
group by d1.id;
Online example: https://rextester.com/JQZ17650
Try something like this:
SELECT id, name, ARRAY_AGG(mapped_id) AS mapped_ids
FROM table1 AS t1
LEFT JOIN table2 AS t2 USING (id)
GROUP BY id, name
I need help with updating table from another table in Postgres Db.
Long story short we ended up with corrupted data in db, and now I need to update one table with values from another.
I have table with this data table wfc:
| step_id | command_id | commands_order |
|---------|------------|----------------|
| 1 | 1 | 0 |
| 1 | 2 | 1 |
| 1 | 3 | 2 |
| 1 | 4 | 3 |
| 1 | 1 | 0 |
| 2 | 2 | 0 |
| 2 | 3 | 1 |
| 2 | 3 | 1 |
| 2 | 4 | 3 |
and I want to update values in command_order column from another table, so I can have result like this:
| step_id | command_id | commands_order|
|---------|------------|---------------|
| 1 | 1 | 0 |
| 1 | 2 | 1 |
| 1 | 3 | 2 |
| 1 | 4 | 3 |
| 1 | 1 | 4 |
| 2 | 2 | 0 |
| 2 | 3 | 1 |
| 2 | 3 | 2 |
| 2 | 4 | 3 |
It was looking like easy task, but problem is to update rows for same command_id, it is writing same value in commands_order
SQL that I tried is:
UPDATE wfc
SET commands_order = CAST(sq.input_step_id as INTEGER)
FROM (
SELECT wfp.step_id, wfp.input_command_id, wfp.input_step_id
from wfp
order by wfp.step_id, wfp.input_step_id
) AS sq
WHERE (wfc.step_id=sq.step_id AND wfc.command_id=CAST(sq.input_command_id as INTEGER));
SQL Fiddle http://sqlfiddle.com/#!15/4efff4/4
I am pretty stuck with this, please help.
Thanks in advance.
Assuming you are trying to number the rows in the order in which they were created, and as long as you understand that ctid will chnage on update and with VACCUUM FULL, you can do the following:
select step_id, command_id, rank - 1 as command_order
from (select step_id, command_id, ctid as wfc_ctid, rank() over
(partition by step_id order by ctid)
from wfc) as wfc_ordered;
This will give you the wfc table with the ordering that you want. If you do update the original table, the ctids will change, so it's probably safer to create a copy of the table with the above query.
Trying to scale this down so the answer is simple. I can probably extrapolate the answers here to apply to a bigger data set.
Given the following table:
+------+-----+
| name | age |
+------+-----+
| a | 5 |
| b | 7 |
| c | 8 |
| d | 8 |
| e | 10 |
+------+-----+
I want to make a table that shows the count of people where their age is equal to or greater than x. For instance, the table about would produce:
+--------------+-------+
| at least age | count |
+--------------+-------+
| 5 | 5 |
| 6 | 4 |
| 7 | 4 |
| 8 | 3 |
| 9 | 1 |
| 10 | 1 |
+--------------+-------+
Is there a single query that can accomplish this task? Obviously, it is easy to write a simple function for it, but I'm hoping to be able to do this quickly with one query.
Thanks!
Yes, what you're looking for is a window function.
with cte_age_count as (
select age,
count(*) c_star
from people
group by age)
select age,
sum(c_star) over (order by age
range between unbounded preceding
and current row)
from cte_age_count
Not syntax checked ... let me know if it works!
Cheers!
I'm trying to get a chart working that shows me the count of work orders that are completed each day after work on a unit (serial number) starts. I'd like to be able to "shadow" multiple serial numbers on top of each other, normalized to a start date of '0'.
Currently I have columns in my data set:
Work order number (0..999), repeats for each serial number
Serial number (0..999)
Work order start date (Datetime)
Work order end date (Datetime)
Say for instance that a new serial number starts each day, contains 5 work orders, and requires 5 days to complete (there are 5 units in WIP at any given time).
The data might look like (dates shown as ints):
| Work order number | Serial number | Work order start date | Work order end date |
| ----------------- | ------------- | --------------------- | ------------------- |
| 1 | 1 | 1 | 2 |
| 2 | 1 | 1 | 3 |
| 3 | 1 | 2 | 4 |
| 4 | 1 | 3 | 5 |
| 5 | 1 | 4 | 5 |
| 1 | 2 | 2 | 3 |
| 2 | 2 | 2 | 4 |
| 3 | 2 | 3 | 5 |
| 4 | 2 | 4 | 6 |
| 5 | 2 | 5 | 6 |
I'm assuming I'll need a calculated column that would perhaps go something like:
[Work order end days since start] =
[Work order end date] - MIN(
IF(*serial number matches current*, [Work order start date], NULL)
)
I (clearly) have no idea how to actually create such a calculated field in Tableau.
The values in the column (same order as the data above) should be:
| Work order end days since start |
| ------------------------------- |
| 1 |
| 2 |
| 3 |
| 4 |
| 4 |
| 1 |
| 2 |
| 3 |
| 4 |
| 4 |
Any guidance or help? Happy to clarify anything as well. Many thanks! Cheers!
You will have better results with this kind of data if you reshape it to have a single date column and add a type column indicating whether the current row describes the start or completion of a workorder.
| Work order number | Serial number | date | type |
Think of each row representing a state change, not a work order.
Open work orders on a particular date would be those that have a start record prior to that date, but don't have a completion record prior to that date. If you define a calculated field as +1 if type = New and -1 if type = Completion, then you can use a running total of that field to view the number of open work orders over time.
I'm using SQL server 2008R2 and I have a view which returns the following:
+----+-------+-------+-------+-------+-------+-------+
| ID | col1A | col1B | col2A | col2B | col3A | col3B |
+----+-------+-------+-------+-------+-------+-------+
| 1 | 1 | 1 | 3 | 5 | 4 | 4 |
| 2 | 1 | 1 | 5 | 5 | 5 | 4 |
| 3 | 3 | 4 | 5 | 5 | 4 | 4 |
| 4 | 1 | 2 | 5 | 5 | 4 | 3 |
| 5 | 1 | 1 | 2 | 2 | 3 | 3 |
+----+-------+-------+-------+-------+-------+-------+
As you can see this view contains column pairs (col1A and col1B), (col2A and col2B), (col3A and col3B).
I need to query this view and find rows where the column pairs contain different values.
So I would be looking to return:
+----+------------+---+-----+
| ID | ColumnType | A | B |
+----+------------+---+-----+
| 1 | Col2 | 3 | 5 |
| 2 | Col3 | 5 | 4 |
| 3 | Col1 | 3 | 4 |
| 4 | Col1 | 1 | 2 |
| 4 | Col3 | 4 | 3 |
+----+------------+---+-----+
I think I need to use UNPIVOT but not sure how – appreciate any suggestions?
Since you are using SQL Server 2008+ you can use CROSS APPLY to unpivot the pair of columns and then you can easily compare the values in the A and B to return the rows that don't match:
select t.ID,
c.ColumnType,
c.A,
c.B
from [dbo].[yourview] t
cross apply
(
values
('Col1', Col1A, Col1B),
('Col2', Col2A, Col2B),
('Col3', Col3A, Col3B)
) c (ColumnType, A, B)
where c.A <> c.B;
If you have different datatypes in your columns, then you'll need to convert the data to the same type. You can do this conversion within the VALUES clause:
select t.ID,
c.ColumnType,
c.A,
c.B
from [dbo].[yourview] t
cross apply
(
values
('Col1', cast(Col1A as varchar(50)), Col1B),
('Col2', cast(Col2A as varchar(50)), Col2B),
('Col3', cast(Col3A as varchar(50)), Col3B)
) c (ColumnType, A, B)
where c.A <> c.B