I have one MySQL table with the following structure:
+-------------+-------+-----------+
| timestamp | value | sensor_id |
+-------------+-------+-----------+
Let's say as an example that there are three possible sensors_ids: id1,id2 and id3.
I would like to perform a query to output the data in the following format:
+-------------+-----------+-----------+-----------+
| timestamp | value_id1 | value_id2 | value_id3 |
+-------------+-----------+-----------+-----------+
It is straightforward to extract data from one ID only but I'm struggling to combine the 3 of them.
SELECT timestamp,
value AS 'value_id1'
FROM table
WHERE sensor_id='id1'
EDIT for clarifications:
(timestamp,sensor_id) is unique over the table
Use conditional aggregation:
select
timestamp,
max(case when sensor_id = 'id1' then value end) value_id1,
max(case when sensor_id = 'id2' then value end) value_id2,
max(case when sensor_id = 'id3' then value end) value_id3
from mytable
group by timestamp
Related
I have an asset_quantities table as below
id | asset_type | quantity | site_id | asset_ids_json
1 'Container' 3 1 [{"id":1,"make":"am1","model":"amo1"},{"id":2,"make":"am1","model":"amo2"},{"id":3,"make":"am3","model":"amo3"}]
2 'Cage' 3 1 [{"id":4,"make":"bm1","model":"bmo1"},{"id":5,"make":"bm2","model":"bmo2"},{"id":6,"make":"bm2","model":"cmo3"}]
3 'Crate' 3 1 [{"id":7,"make":"cm1","model":"cmo1"},{"id":8,"make":"cm1","model":"cmo1"},{"id":9,"make":"cm1","model":"cmo2"}]
I want to write a SQL query in Postgres that will give me the quantity count of each asset type for a given make or model.
E.g. If I wanted to fetch the quantity for each asset type where make='am1',
site_id | Container_qty | Cage_qty | Crate_qty
1 2 0 0
E.g. If I wanted to fetch the quantity for each asset type where make='cm1', the result set would look like
site_id | Container_qty | Cage_qty | Crate_qty
1 0 0 3
I have written the query below to pivot the values from the 'asset_type' rows into columns but can't figure out how to filter and aggregate the counts based on the attributes inside the field 'asset_ids_json'. It is safe to assume that the length of the json array inside asset_ids_json will always be the same as the value in the 'quantity' column.
select
aq.site_id,
sum(case when aq.asset_type = 'Container' then aq.quantity end) container_qty,
sum(case when aq.asset_type = 'Cage' then aq.quantity end) cage_qty ,
sum(case when aq.asset_type = 'Crate' then aq.quantity end) crate_qty,
from asset_quantities aq
group by aq.site_id;
The crux of my question is how can I filter & aggregate results based on the attributes inside the json column 'asset_ids_json'. I'm using Postgres 9.4.
step-by-step demo:db<>fiddle
SELECT
site_id,
SUM(case when asset_type = 'Container' then quantity end) container_qty,
SUM(case when asset_type = 'Cage' then quantity end) cage_qty ,
SUM(case when asset_type = 'Crate' then quantity end) crate_qty
FROM (
SELECT DISTINCT ON (id)
site_id,
asset_type,
quantity
FROM asset_quantities aq,
json_array_elements(asset_ids_json)
WHERE value ->> 'make' = 'cm1'
) s
GROUP BY site_id
To get a WHERE clause over the content of a JSON array you have to expand the array. json_array_elements() creates one row for each element. With that it is possible to ask for a certain value.
Because of this expansion the current rows are multiplied (three times here because there are three elements in the array). Because you are only interested in the original site_id, asset_type and quantity data which were simply copied into the new records, you can eliminate them with a DISTINCT. DISTINCT ON checks for distinct values of each id. So if two JSON array would contain the same key/value both will be saved.
I have an old database of entries from an abandoned "Joomgalaxy" Joomla plugin.
There are three tables, joomgalaxy_entries, joomgalaxy_fields, and joomgalaxy_entries_data
The id from the entries table matches the entry_id in the entries_data table, but the actual field name is saved in another table, fields
Can someone please help me with the correct SQL statement to obtain results like you can see below in Ultimate Goal? My MySQL knowledge is very basic, and from my searching it sounds like I need to use a LEFT JOIN, but I have no idea how to use the value from field_name as the column name for returned values
Thank You!!
joomgalaxy_entries
---------------------------------------
| id | title | longitude | latitude |
---------------------------------------
| 50 | John | -79.333333 | 43.669999 |
| 51 | Bob | -79.333333 | 43.669999 |
---------------------------------------
joomgalaxy_fields
This is just two examples below to keep it simple, there are more than just these two, so it would have to be able to handle dynamically using the field_name as the column name.
--------------------------------
| id | field_type | field_name |
--------------------------------
| 1 | textbox | websiteurl |
| 2 | dropdown | occupation |
--------------------------------
joomgalaxy_entries_data
"Technically" there shouldn't be any duplicate entries (fieldid and entry_id), so from my understanding that shouldn't affect using the field_name from above as the column name, but what if there ends up being one?
-------------------------------------
| fieldid | field_value | entry_id |
-------------------------------------
| 1 | google.com | 50 |
| 2 | unemployed | 50 |
| 1 | doctor.com | 51 |
| 2 | doctor | 51 |
-------------------------------------
Ultimate Goal
Ultimately trying to get this type of result, so I can then use that statement in MySQL Workbench to export the data that would look like this:
------------------------------------------------------------------
| id | title | longitude | latitude | websiteurl | occupation |
------------------------------------------------------------------
| 50 | John | -79.333333 | 43.669999 | google.com | unemployed |
| 51 | Bob | -79.333333 | 43.669999 | doctor.com | doctor |
------------------------------------------------------------------
EDIT:
There are more than just the two fields websiteurl and occupation, I was just using those two as examples, there are numerous fields that are all different, so in theory pulling the value from field_name would be used for the column name
You can use some conditional logic, like a CASE statement, along with an aggregate function like max() or min() to return those values as columns:
SELECT je.id,
je.title,
je.longitude,
je.latitude,
max(case when jf.fieldid = 1 then jed.field_value end) as WebsiteUrl,
max(case when jf.fieldid = 2 then jed.field_value end) as Occupation
FROM joomgalaxy_entries je
INNER JOIN joomgalaxy_entries_data jed
on je.id = jed.entry_id
GROUP BY je.id,
je.title,
je.longitude,
je.latitude
Using an INNER JOIN will only return the joomgalaxy_entries rows that have values in each table, if you want to return all joomgalaxy_entries even if there are no matching rows to join on in the other tables, then change the INNER JOIN to a LEFT JOIN.
You can write a simple SELECT query like this:
SELECT je.id, je.title, je.longitude, je.latitude,
(SELECT field_value FROM joomgalaxy_entries_data WHERE fieldid = 1 AND entry_id = je.id) AS websiteurl,
(SELECT field_value FROM joomgalaxy_entries_data WHERE fieldid = 2 AND entry_id = je.id) AS occupation
FROM joomgalaxy_entries je;
First step is easy:
SELECT JE.id, JE.title, JE.longitude, JE.latitude
FROM joomgalaxy_entries JE
Now you need to JOIN:
SELECT JE.id, JE.title, JE.longitude, JE.latitude,
JD.*
FROM joomgalaxy_entries JE
JOIN joomgalaxy_entries_data JD
ON JE.id = JD.entry_id
Now you need convert rows to columns
SELECT JE.id, JE.title, JE.longitude, JE.latitude,
MIN(CASE WHEN fieldid = 1 THEN JD.field_value END) as WebsiteUrl,
MIN(CASE WHEN fieldid = 2 THEN JD.field_value END) as Occupation
FROM joomgalaxy_entries JE
JOIN joomgalaxy_entries_data JD
ON JE.id = JD.entry_id
GROUP BY JE.id, JE.title, JE.longitude, JE.latitude
This depend on you only have two field for each entry, if number of field is dynamic you would need a different aproach.
This should work:
select id, title, longitude, latitude,
(select field_value from joomgalaxy_entries_data jed
where fieldid = (select id from joomgalaxy_fields
where field_name = 'websiteurl')
and jed.entry_id = je.id
) as websiteurl,
(select field_value from joomgalaxy_entries_data jed
where fieldid = (select id from joomlgalaxy_fields
where field_name = 'occupation')
and jed.entry_id = je.id) as occupation
from joomgalaxy_entries je;
Note that the reason to have a left join would be if either websiteurl or occupation were null, however, this solution should work in that case anyway.
Well, that certainly makes it a bit more difficult... :) Honestly, I'm not sure what you're asking is possible with a static sql query. I'm sure someone will speak up, however, if I'm wrong.
That said, I do have a few options you can try:
Option 1 - Generate the SQL Dynamically
Assuming this is mysql, if you execute the following SQL, it will generate the subqueries dynamically:
select concat('(select field_value from joomgalaxy_entries_data jed ',
'where fieldid = (select id from joomgalaxy_fields ',
'where field_name = ''', field_name, ''') ',
'and jed.entry_id = je.id) as ', field_name, ',')
from joomgalaxy_fields;
Take the result of that command, copy-paste it into a text editor and add the following at the beginning:
select id, title, longitude, latitude,
And the rest of this at the end:
from joomgalaxy_entries je;
Then run your new uber-query and go grab a cup of copy, lunch, or a good night's sleep depending on how much data is in your database.
Alternatively, you could add all of this to a stored procedure so you don't have to hand edit the SQL. Also, note that my syntax works for MySQL. Other databases have different concatenation operators so you may have to work around that if applicable. Also, with 50+ subqueries there is a good chance this uber-query will be quite slow, maybe too slow to make this option viable.
Option 2 - Create a table structured the way you want, and populate it
Hopefully, this is self-explanatory, but just create a new table with all of the necessary columns from the joomgalaxy_fields table. Then populate each column separately with a long series of what should be pretty straightforward sql commands. Granted this option is only viable if the database is no longer in use which I believe you indicated. From there the result is just:
select * from my_new_table;
I am looking for a way to return an ID only if NO rows hold a certain value
For example:
*ID* | *Date*
1 | 01/01/2001
1 | 02/02/2002
1 | 03/03/2003
If I want SQL to return the ID only if no dates are equal to 02/02/2002, how would I script that? I have tried and failed with the below:
select *ID*
from (example)
where date != 02/02/2002
The problem is that this still returns the ID - 1, as the first and last row do not equal 02/02/2002. What I am aiming for is no returned results because at least one row held the matching date.
I would need the script to completely skip the ID when there is a matching date in any row.
For clarity the below should return the ID when using the same 'select' as above because no dates are matching:
*ID* | *Date*
2 | 03/03/2003
2 | 04/04/2004
2 | 05/05/2005
You need Group By and Having clause
select ID
From yourtable
group by ID
Having count (case when date != '02/02/2002' then 1 end) = count(*)
As mentioned by mathguy, this also works
select ID
From yourtable
group by ID
Having count(case when date = '02/02/2002' then 1 end) = 0
I have table like this:
+----+---------+---------+--------+
| id | value_x | created | amount |
+----+---------+---------+--------+
value_x is set of six strings, lets say "one", "two", "three", etc.
I need to create report like this:
+--------------+-------------------------+-------------------+----------------------+
| day_of_month | "one" | "two" | [etc.] |
+--------------+-------------------------+-------------------+----------------------+
| 01-01-2011 | "sum(amount) where value_x = colum name" for this specific day |
+--------------+-------------------------+-------------------+----------------------+
Most obvious solution is:
SELECT SUM(amount), DATE(created) FROM `table_name` WHERE value_x=$some_variable GROUP BY DATE(created)
And loop this query six times with another value for $some_variable in every iteration, but I'm courious if is it possible to do this in single query?
What you're asking is called a "pivot table" and is typically achieved as below. The idea is for each potential value of value_x you either produce a 1 or 0 per row and sum 1's and 0's to get the sum for each value.
SELECT
DATE(created),
SUM(CASE WHEN value_x = 'one' THEN SUM(amount) ELSE 0 END) AS 'one',
SUM(CASE WHEN value_x = 'one' THEN SUM(amount) ELSE 0 END) AS 'two',
SUM(CASE WHEN value_x = 'one' THEN SUM(amount) ELSE 0 END) AS 'three',
etc...
FROM table_name
GROUP BY YEAR(created), MONTH(created), DAY(created)
This will come close:
SELECT
s.day_of_month
,GROUP_CONCAT(CONCAT(s.value_x,':',s.amount) ORDER BY s.value_x ASC) as output
FROM (
SELECT DATE(created) as day_of_month
,value_x
,SUM(amount) as amount
FROM table1
GROUP BY day_of_month, value_x
) s
GROUP BY s.day_of_month
You will need to read the output and look for the value_x prior to the : to place the items in the proper column.
The benefit of this approach over #Michael's approach is that you do not need to know the possible values of field value_x beforehand.
I am attempting to narrow results of an existing complex query based on conditional matches on multiple columns within the returned data set. I'll attempt to simplify the data as much as possible here.
Assume that the following table structure represents the data that my existing complex query has already selected (here ordered by date):
+----+-----------+------+------------+
| id | remote_id | type | date |
+----+-----------+------+------------+
| 1 | 1 | A | 2011-01-01 |
| 3 | 1 | A | 2011-01-07 |
| 5 | 1 | B | 2011-01-07 |
| 4 | 1 | A | 2011-05-01 |
+----+-----------+------+------------+
I need to select from that data set based on the following criteria:
If the pairing of remote_id and type is unique to the set, return the row always
If the pairing of remote_id and type is not unique to the set, take the following action:
Of the sets of rows for which the pairing of remote_id and type are not unique, return only the single row for which date is greatest and still less than or equal to now.
So, if today is 2011-01-10, I'd like the data set returned to be:
+----+-----------+------+------------+
| id | remote_id | type | date |
+----+-----------+------+------------+
| 3 | 1 | A | 2011-01-07 |
| 5 | 1 | B | 2011-01-07 |
+----+-----------+------+------------+
For some reason I'm having no luck wrapping my head around this one. I suspect the answer lies in good application of group by, but I just can't grasp it. Any help is greatly appreciated!
/* Rows with exactly one date - always return regardless of when date occurs */
SELECT id, remote_id, type, date
FROM YourTable
GROUP BY remote_id, type
HAVING COUNT(*) = 1
UNION
/* Rows with more than one date - Return Max date <= NOW */
SELECT yt.id, yt.remote_id, yt.type, yt.date
FROM YourTable yt
INNER JOIN (SELECT remote_id, type, max(date) as maxdate
FROM YourTable
WHERE date <= DATE(NOW())
GROUP BY remote_id, type
HAVING COUNT(*) > 1) sq
ON yt.remote_id = sq.remote_id
AND yt.type = sq.type
AND yt.date = sq.maxdate
The group by clause groups all rows that have identical values of one or more columns together and returns one row in the result set for them. If you use aggregate functions (min, max, sum, avg etc.) that will be applied for each "group".
SELECT id, remote_id, type, max(date)
FROM blah
GROUP BY remote_id, date;
I'm not whore where today's date comes in, but assumed that was part of the complex query that you didn't describe and I assume isn't directly relevant to your question here.
Try this:
SELECT a.*
FROM table a INNER JOIN
(
select remote_id, type, MAX(date) date, COUNT(1) cnt from table
group by remote_id, type
) b
WHERE a.remote_id = b.remote_id,
AND a.type = b.type
AND a.date = b.date
AND ( (b.cnt = 1) OR (b.cnt>1 AND b.date <= DATE(NOW())))
Try this
select id, remote_id, type, MAX(date) from table
group by remote_id, type
Hey Carson! You could try using the "distinct" keyword on those two fields, and in a union you can use Count() along with group by and some operators to pull non-unique (greatest and less-than today) records!