I have two tables, one is a list os stores and attributes, the second is a list of allocationsa based on these attributes.
The attribute table (stores_metadata)
| key | store_key | field | value
| 1 | 1 | size | Large
| 2 | 1 | dist | Midlands
| 3 | 2 | size | Medium
| 4 | 3 | dist | South
The allocation table (allocation)
| key | ticket_key | field | value | count
| 1 | 1 | size | Large | 10
| 2 | 1 | size | Medium| 5
I've managed to get the allocations working using the code:
SELECT store_key, quantity FROM
allocation
INNER JOIN store_metadata
ON allocation.`field` = store_metadata.`field`
AND allocation.`value` = store_metadata.`value`
This returns a list of the stores and how many items they should recieve, what I now need to do it order the stores by the distribution attribute.
Any help would be greatly appreciated.
The question isn't asked very well.
To perform ordering by any column in your result set add ORDER BY [column] to the end of the query. E.g.
SELECT store_key, quantity FROM
allocation
INNER JOIN store_metadata
ON allocation.`field` = store_metadata.`field`
AND allocation.`value` = store_metadata.`value`
ORDER BY allocation.`field`;
Related
For example, there are three rooms.
1|gold_room|1,2,3
2|silver_room|1,2,3
3|brown_room|2,4,6
4|brown_room|3
5|gold_room|4,5,6
Then, I'd like to get
gold_room|1,2,3,4,5,6
brown_room|2,3,4,6
silver_room|1,2,3
How can I achieve this?
I've tried: select * from room group by name; And it only prints the first row. And I know CONCAT() can combine two string values.
Please use below query,
select col2, GROUP_CONCAT(col3) from data group by col2;
Below is the Test case,
https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=ab35e8d66ffe3ac6436c17faf97ee9af
I'm not making an assumption that the lists don't have elements in common on separate rows.
First create a table of integers.
mysql> create table n (n int primary key);
mysql> insert into n values (1),(2),(3),(4),(5),(6);
You can join this to your rooms table using the FIND_IN_SET() function. Note that this cannot be optimized. It will execute N full table scans. But it does create an interim set of rows.
mysql> select * from n inner join rooms on find_in_set(n.n, rooms.csv) order by rooms.room, n.n;
+---+----+-------------+-------+
| n | id | room | csv |
+---+----+-------------+-------+
| 2 | 3 | brown_room | 2,4,6 |
| 3 | 4 | brown_room | 3 |
| 4 | 3 | brown_room | 2,4,6 |
| 6 | 3 | brown_room | 2,4,6 |
| 1 | 1 | gold_room | 1,2,3 |
| 2 | 1 | gold_room | 1,2,3 |
| 3 | 1 | gold_room | 1,2,3 |
| 4 | 5 | gold_room | 4,5,6 |
| 5 | 5 | gold_room | 4,5,6 |
| 6 | 5 | gold_room | 4,5,6 |
| 1 | 2 | silver_room | 1,2,3 |
| 2 | 2 | silver_room | 1,2,3 |
| 3 | 2 | silver_room | 1,2,3 |
+---+----+-------------+-------+
Use GROUP BY to reduce these rows to one row per room. Use GROUP_CONCAT() to put the integers together into a comma-separated list.
mysql> select room, group_concat(distinct n.n order by n.n) as csv
from n inner join rooms on find_in_set(n.n, rooms.csv) group by rooms.room
+-------------+-------------+
| room | csv |
+-------------+-------------+
| brown_room | 2,3,4,6 |
| gold_room | 1,2,3,4,5,6 |
| silver_room | 1,2,3 |
+-------------+-------------+
I think this is a lot of work, and impossible to optimize. I don't recommend it.
The problem is that you are storing comma-separated lists of numbers, and then you want to query it as if the elements in the list are discrete values. This is a problem for SQL.
It would be much better if you did not store your numbers in a comma-separated list. Store multiple rows per room, with one number per row. You can run a wider variety of queries if you do this, and it will be more flexible.
For example, the query you asked about, to produce a result with numbers in a comma-separated list is more simple, and you don't need the extra n table:
select room, group_concat(n order by n) as csv from rooms group by room
See also my answer to Is storing a delimited list in a database column really that bad?
I have inherrited a DB that I've been tasked to mine for Data.
There are 2 tables that are loosely associated - atm and dslams.
The atm table contains "remotename", "rst", and "CardNumber" fields that relate to the dslams "hostname" field.
The atm table contains the port information for the dslam cards and the dslams table contains the information about the dslam card itself.
I've been tasked with printing out all the locations (dslams.name) that have a certain type of card (dslams.model="6256") and a count of all the ports on that card that have a certain level of service (atm.speed LIKE "RI_%%09" OR atm.speed LIKE "RI%%1%").
I've crafted the following statement which almost works...
SELECT distinct(dslams.name) AS Remote, Count(atm.speed) AS Customers, dslams.model
FROM dslams
LEFT JOIN atm
ON (dslams.hostname = CONCAT(atm.remotename,'-',atm.rst,'-S',atm.CardNumber)) AND (atm.speed LIKE "RI_%_%09" OR atm.speed LIKE "RI_%_%1_%")
GROUP BY dslams.name
HAVING dslams.model="6256"
ORDER BY dslams.name;
This prints out exactly what I need for all but 1 of the locations.
ie.
MariaDB [dsl]> SELECT distinct(dslams.name) AS Remote, Count(atm.speed) AS Customers, dslams.model
-> FROM dslams
-> LEFT JOIN atm
-> ON (dslams.hostname = CONCAT(atm.remotename,'-',atm.rst,'-S',atm.CardNumber)) AND (atm.speed LIKE "RI_%_%09" OR atm.speed LIKE "RI_%_%1_%")
-> GROUP BY dslams.name
-> HAVING dslams.model="6256"
-> ORDER BY dslams.name;
+---------+-----------+-------+
| Remote | Customers | model |
+---------+-----------+-------+
| ANTH-C2 | 1 | 6256 |
| BETY-C2 | 1 | 6256 |
| BHOT-C2 | 6 | 6256 |
| BNSH-C2 | 1 | 6256 |
| BUG2-C2 | 1 | 6256 |
| CCRK-C2 | 0 | 6256 |
...
| STLN-C2 | 1 | 6256 |
| SUMR-C2 | 2 | 6256 |
...
| WGRV-C2 | 0 | 6256 |
+---------+-----------+-------+
63 rows in set (0.34 sec)
For some reason there's one location that's not getting counted - STWL-C2.
MariaDB [dsl]> SELECT distinct(name), model FROM dslams WHERE model="6256" order by name;
+---------+-------+
| name | model |
+---------+-------+
| ANTH-C2 | 6256 |
| BETY-C2 | 6256 |
| BHOT-C2 | 6256 |
| BNSH-C2 | 6256 |
| BUG2-C2 | 6256 |
| CCRK-C2 | 6256 |
...
| STWL-C2 | 6256 |
...
| WGRV-C2 | 6256 |
+---------+-------+
64 rows in set (0.00 sec)
There's no difference in the tables between the STWL-C2 location and the other locations so it should print out with a count of 0.
Can anyone help me figure out why that 1 location is being missed?
Any help or direction would be appreciated as I am a rookie SQL programmer trying to understand this as best I can.
Best Regards,
Joe
Don't use HAVING dslams.model = '6256', put that in the WHERE clause. When you use HAVING, it filters after grouping. When you group by name, the result can contain the model from any row in the group, and it won't necessarily choose model = '6256'.
SELECT dslams.name AS Remote, Count(atm.speed) AS Customers, dslams.model
FROM dslams
LEFT JOIN atm
ON (dslams.hostname = CONCAT(atm.remotename,'-',atm.rst,'-S',atm.CardNumber)) AND (atm.speed LIKE "RI_%_%09" OR atm.speed LIKE "RI_%_%1_%")
WHERE dslams.model = '6256'
GROUP BY dslams.name
ORDER BY dslams.name;
I created a table (t_subject) like this
| id | description | enabled |
|----|-------------|---------|
| 1 | a | 1 |
| 2 | b | 1 |
| 3 | c | 1 |
And another table (t_place) like this
| id | description | enabled |
|----|-------------|---------|
| 1 | d | 1 |
| 2 | e | 1 |
| 3 | f | 1 |
Right now data from t_subject is used for each of t_place records, to show HTML dropdowns, with all the results from t_subject.
So I simply do
SELECT * FROM t_subject WHERE enabled = 1
Now just for one of t_place records, one record from t_subject should be hidden.
I don't want to simply delete it with javascript, since I want to be able to customize all of the dropdowns if anything changes.
So the first thing I though was to add a place_id column to t_subject.
But this means I have to duplicate all of t_subject records, I would have 3 of each, except one that would have 2.
Is there any way to avoid this??
I thought adding an id_exclusion column to t_subject so I could duplicate records only whenever a record is excluded from another id from t_place.
How bad would that be?? This way I would have no duplicates, so far.
Hope all of this makes sense.
While you only need to exclude one course, I would still recommend setting up a full 'place-course' association. You essentially have a many-to-many relationship, despite not explicitly linking your tables.
I would recommend an additional 'bridging' or 'associative entity' table to represent which courses are offered at which places. This new table would have two columns - one foreign key for the ID of t_subject, and one for the ID of t_place.
For example (t_place_course):
| place_id | course_id |
|----------|-----------|
| 1 | 1 |
| 1 | 2 |
| 1 | 3 |
| 2 | 1 |
| 2 | 2 |
| 2 | 3 |
| 3 | 1 |
| 3 | 3 |
As you can see in my example above, place 3 doesn't offer course 2.
From here, you can simply query all of the courses available for a place by querying the place_id:
SELECT * from t_place_course WHERE place_id = 3
The above will return both courses 1 and 3.
You can optionally use a JOIN to get the other information about the course or place, such as the description:
SELECT `t_course`.`description`
FROM `t_course`
INNER JOIN `t_place_course`
ON `t_course`.`id` = `t_place_course`.`course_id`
INNER JOIN `t_place`
ON `t_place`.`id` = `place_id`
I want to select value from table sorted by a certain order.
I have a table called test that looks like this:
| date | code | value |
+----------+-----------+----------+
| 20050104 | 000005.SZ | -6359.19 |
| 20050104 | 600601.SH | -7876.34 |
| 20050104 | 600602.SH | -25693.3 |
| 20050104 | 600651.SH | NULL |
| 20050104 | 600652.SH | -15309.9 |
...
| 20050105 | 000005.SZ | -4276.28 |
| 20050105 | 600601.SH | -3214.56 |
...
| 20170405 | 000005.SZ | 23978.13 |
| 20170405 | 600601.SH | 32212.54 |
Right now I want to select only one date, say date = 20050104, and then sort the data by a certain order (the order that each stock was listed in the stock market).
I have another table called stock_code which stores the correct order:
+---------+-----------+
| code_id | code |
+---------+-----------+
| 1 | 000002.SZ |
| 2 | 000004.SZ |
| 3 | 600656.SH |
| 4 | 600651.SH |
| 5 | 600652.SH |
| 6 | 600653.SH |
| 7 | 600654.SH |
| 8 | 600602.SH |
| 9 | 600601.SH |
| 10 | 000005.SZ |
...
I want to sorted the selected data by stock_code(code_id), but I don't want to use join because it takes too much time. Any thoughts?
I tried to use field but it gives me an error, please tell me how to correct it or give me an even better idea.
select * from test
where date = 20050104 and code in (select code from stock_code order by code)
order by field(code, (select code from stock_code order by code));
Error Code: 1242. Subquery returns more than 1 row
You told us that you don't want to join because it takes too much time, but the following join query is probably the best option here:
SELECT t.*
FROM test t
INNER JOIN stock_code sc
ON t.code = sc.code
WHERE t.date = '20050104'
ORDER BY sc.code_id
If this really runs slowly, then you should check to make sure you have indices setup on the appropriate columns. In this case, indices on the code columns from both tables as well as an index on test.date should be very helpful.
ALTER TABLE test ADD INDEX code_idx (code)
ALTER TABLE test ADD INDEX date_idx (date)
ALTER TABLE code ADD INDEX code_idx (code)
Some background: an 'image' is part of one 'photoshoot', and may be a part of zero or many 'galleries'. My tables:
'shoots' table:
+----+--------------+
| id | name |
+----+--------------+
| 1 | Test shoot |
| 2 | Another test |
| 3 | Final test |
+----+--------------+
'images' table:
+----+-------------------+------------------+
| id | original_filename | storage_location |
+----+-------------------+------------------+
| 1 | test.jpg | store/test.jpg |
| 2 | test.jpg | store/test.jpg |
| 3 | test.jpg | store/test.jpg |
+----+-------------------+------------------+
'shoot_images' table:
+----------+----------+
| shoot_id | image_id |
+----------+----------+
| 1 | 1 |
| 1 | 2 |
| 3 | 3 |
+----------+----------+
'gallery_images' table:
+------------+----------+
| gallery_id | image_id |
+------------+----------+
| 1 | 1 |
| 1 | 2 |
| 2 | 3 |
| 3 | 1 |
| 4 | 1 |
+------------+----------+
What I'd like to get back, so I can say 'For this photoshoot, there are X images in total, and these images are featured in Y galleries:
+----+--------------+-------------+---------------+
| id | name | image_count | gallery_count |
+----+--------------+-------------+---------------+
| 3 | Final test | 1 | 1 |
| 2 | Another test | 0 | 0 |
| 1 | Test shoot | 2 | 4 |
+----+--------------+-------------+---------------+
I'm currently trying the SQL below, which appears to work correctly but only ever returns one row. I can't work out why this is happening. Curiously, the below also returns a row even when 'shoots' is empty.
SELECT shoots.id,
shoots.name,
COUNT(DISTINCT shoot_images.image_id) AS image_count,
COUNT(DISTINCT gallery_images.gallery_id) AS gallery_count
FROM shoots
LEFT JOIN shoot_images ON shoots.id=shoot_images.shoot_id
LEFT JOIN gallery_images ON shoot_images.image_id=gallery_images.image_id
ORDER BY shoots.id DESC
Thanks for taking the time to look at this :)
You are missing the GROUP BY clause:
SELECT
shoots.id,
shoots.name,
COUNT(DISTINCT shoot_images.image_id) AS image_count,
COUNT(DISTINCT gallery_images.gallery_id) AS gallery_count
FROM shoots
LEFT JOIN shoot_images ON shoots.id=shoot_images.shoot_id
LEFT JOIN gallery_images ON shoot_images.image_id=gallery_images.image_id
GROUP BY 1, 2 -- Added this line
ORDER BY shoots.id DESC
Note: The SQL standard allows GROUP BY to be given either column names or column numbers, so GROUP BY 1, 2 is equivalent to GROUP BY shoots.id, shoots.name in this case. There are many who consider this "bad coding practice" and advocate always using the column names, but I find it makes the code a lot more readable and maintainable and I've been writing SQL since before many users on this site were born, and it's never cause me a problem using this syntax.
FYI, the reason you were getting one row before, and not getting and error, is that in mysql, unlike any other database I know, you are allowed to omit the group by clause when using aggregating functions. In such cases, instead of throwing a syntax exception, mysql returns the first row for each unique combination of non-aggregate columns.
Although at first this may seem abhorrent to SQL purists, it can be incredibly handy!
You should look into the MySQL function group by.