I have a SQL Table that I'm trying to query and order the return. I am able to query just fine and the SQL Statement that I'm using is also working with the exception of the last ORDER BY statement that I need to execute. The sort order is as follows:
Sort the Status column so that 'open' is on top, 'closed' on bottom
Order the 'Flag' column so that empty (null) values are on bottom (above Status = Closed) and values on top
Order the results of items 1 and 2 by the Number column
Here is an example of the raw data:
| Flag | Number | Status |
|------------------------|
| a | 1 | open |
| | 5 | open |
| | 3 | closed |
| a | 4 | open |
| a | 2 | closed |
Here is what I'm going for:
| Flag | Number | Status |
|------------------------|
| a | 1 | open |
| a | 4 | open |
| | 5 | open |
| a | 2 | closed |
| | 3 | closed |
The query statement that I'm using is as follows:
sqlCom.CommandText = "SELECT * FROM Questions
WHERE Identifier = #identifier
AND Flag <> 'DELETED'
ORDER BY Status DESC
, (CASE WHEN Flag is null THEN 1 ELSE 0 END) ASC
, Flag DESC
, [Number] * 1 ASC";
Now, everything works fine, but the 3rd item above (sorting by Number column) doesn't work. Any ideas why?
What I'm currently getting:
| Flag | Number | Status |
|------------------------|
| a | 4 | open | <-- Out of order. Should be below the next record
| a | 1 | open | <-- Out of order. Should be one record up
| | 5 | open | <-- OK
| | 6 | open | <-- OK
| | 3 | closed | <-- OK
| a | 2 | closed | <-- OK
Thanks in advance for any helpful input. I have tried fiddling with the query in SSMS but no luck.
Your third sort expression is on Flag. Those values are being sorted alphabetically before the QNumber sort applies. And note that case matters in the ordering as well.
Here's how I would write it:
ORDER BY
Status DESC, -- might be better to use a case expression
CASE WHEN Flag IS NOT NULL THEN 0 ELSE 1 END,
QNumber
Since your data in the examples contradicts the data in the screenshot, it's not clear whether you needed to remove the third sort column entirely or just sort by ignoring the case of the text.
Related
I'm using nextcloud to track data via the forms app, the table oc_forms_v2_submissions contains the entries:
SELECT * FROM `oc_forms_v2_submissions` WHERE `form_id` = 3;
+----+---------+--------------------------------------------+------------+
| id | form_id | user_id | timestamp |
+----+---------+--------------------------------------------+------------+
| 8 | 3 | anon-user-96684f301d22e7be44f07780a9bffe06 | 1663789158 |
| 9 | 3 | anon-user-a1eaa4f939b59e00b403c046410788aa | 1663835954 |
| 10 | 3 | anon-user-440d0dbe9c107492b6ec1a06d98004a8 | 1663942458 |
+----+---------+--------------------------------------------+------------+
the second table is oc_forms_v2_answers
SELECT * FROM `oc_forms_v2_answers`;
+----+---------------+-------------+-----------------------+
| id | submission_id | question_id | text |
+----+---------------+-------------+-----------------------+
| 10 | 8 | 7 | foo |
| 11 | 9 | 7 | bar |
| 12 | 10 | 7 | foo |
+----+---------------+-------------+-----------------------+
So basically i need to the take all the id entries from table submissions and match them with submission_id from answers and I want to have the data from the text column.
SELECT oc_forms_v2_submissions.id as submission_id
FROM `oc_forms_v2_submissions`
RIGHT JOIN `oc_forms_v2_answers` ON submission_id=oc_forms_v2_answers.submission_id;
This is all i could come up with so far but that returns only the submission_id field and everything triplicated :-D
+---------------+
| submission_id |
+---------------+
| 8 |
| 8 |
| 8 |
| 9 |
| 9 |
| 9 |
| 10 |
| 10 |
| 10 |
+---------------+
Edit:
The updated query still does not get me the field from oc_forms_answers:
SELECT oc_forms_v2_submissions.id as submission_id
FROM `oc_forms_v2_submissions`
RIGHT JOIN `oc_forms_v2_answers` ON oc_forms_v2_submissions.id=oc_forms_v2_answers.submission_id where form_id="3";
that is because you are comparing to identical columns, you need in the ON Clause, the link columns of both tables
Also you can use alias, to reduce the typing time
The RIGHT JOIN would also combine all answers with thes ubmission, but you you will never have more submission as answer, so a LEFT JOIN would gove ou all submissions even if there is no answer
SELECT oc_forms_v2_submissions.id as submission_id
FROM `oc_forms_v2_submissions`
LEFT JOIN `oc_forms_v2_answers` ON oc_forms_v2_submissions.id=oc_forms_v2_answers.submission_id;
This should do the trick (just update the correct naming of columns and tables)
SELECT s.id as submission_id, a.txt FROM submissions s
LEFT JOIN answers a
ON s.id=a.submission_id;
You can check this here in db-fiddle. I've used your info for creating a DB, so WHERE clause is missing but all the rest should give you results you're after.
I am new to working with databases and I want to make sure I understand the best way to add or remove data from a database without making a mess of any related data.
Here is a scenario I am working with:
I have a Tags table, with an Identity ID column. The Tags can be selected via the web application to categorize stories that are submitted by a user. When the database was first seeded; like tags were seeded in order together. As you can see all the Campuses (cities) were 1-4, the Colleges (subjects) are 5-7, and Populations are 8-11.
If this database is live in production and the client wants to add a new Campus (City) tag, what is the best way to do this?
All the other city tags are sort of organized at the top, it seems like the only option is to insert any new tags at to bottom of the table, where they will end up taking whatever the next ID available is. I suppose this is fine because the Display category column will allow us to know which categories these new tags actually belong to.
Is this typical? Is there better ways to set up the database or handle this situation such that everything remains more organized?
Thank you
+----+------------------+---------------+-----------------+--------------+--------+----------+
| ID | DisplayName | DisplayDetail | DisplayCategory | DisplayOrder | Active | ParentID |
+----+------------------+---------------+-----------------+--------------+--------+----------+
| 1 | Albany | NULL | 1 | 0 | 1 | NULL |
| 2 | Buffalo | NULL | 1 | 1 | 1 | NULL |
| 3 | New York City | NULL | 1 | 2 | 1 | NULL |
| 4 | Syracuse | NULL | 1 | 3 | 1 | NULL |
| 5 | Business | NULL | 2 | 0 | 1 | NULL |
| 6 | Dentistry | NULL | 2 | 1 | 1 | NULL |
| 7 | Law | NULL | 2 | 2 | 1 | NULL |
| 8 | Student-Athletes | NULL | 3 | 0 | 1 | NULL |
| 9 | Alumni | NULL | 3 | 1 | 1 | NULL |
| 10 | Faculty | NULL | 3 | 2 | 1 | NULL |
| 11 | Staff | NULL | 3 | 3 | 1 | NULL |
+----+------------------+---------------+-----------------+--------------+--------+----------+
The terms "top" and "bottom" which you use aren't really applicable. "Albany" isn't at the "Top" of the table - it's merely at the top of the specific view you see when you query the table without specifying a meaningful sort order. It defaults to a sort order based on the Id or an internal ROWID parameter, which isn't the logical way to show this data.
Data in the table isn't inherently ordered. If you want to view your tags organized by their category, simply order your query by DisplayCategory (and probably by DisplayOrder afterwards), and you'll see your data properly organized. You can even create a persistent View that sorts it that way for your convenience.
I'm kinda confused on how this thing can be done.
I have a database table having these values:
| id | file_type | code | position |
-------------------------------------
| 1 | Order | SO | 1 |
| 2 | Order | 1-SO | 7 |
| 3 | Order | 1_SO | 7 |
Now, I want to get the position and the file type of my filename so I come up with this query:
SET #FileName = '1-SO1234567890.pdf'
SELECT *
FROM tbl_FileTypes
WHERE CHARINDEX(code,#FileName)> 0
Sadly, I'm getting two results here, I only need the data with the "1-SO" result.
| id | file_type | code | position |
-------------------------------------
| 1 | Order | SO | 1 |
| 2 | Order | 1-SO | 7 |
I believe that my WHERE Clause causes this to happen.
Is there any better way for me to get my desired results?
Thank you very much in advance.
You might want to use SUBSTRING instead (assuming T-SQL):
WHERE code = SUBSTRING(#FileName,1, LEN(code));
Which checks if the first n-chars of FileName equal a given code.
DEMO
well
SET #FileName = '1-SO1234567890.pdf'
SELECT *
FROM tbl_FileTypes
WHERE CHARINDEX(code,#FileName) = 1
would work in this case but if you had a code '1-SOS' it's going to fail again.
Since you are cheking left most characters, you could also use LEFT() function as below. Also use TOP (1) to get a single record and consider ordering as needed.
SELECT TOP (1) *
FROM tbl_FileTypes
WHERE LEFT(#FileName,LEN(code)) = code
--ORDER BY yourCol
Sorry for the title, perhaps it's not very clear.
I have some SQL queries in a script that depend on each other.
The script uses a temporary table in which the data is inserted (the #temp_data table).
This is the expected output:
___________________________________
| speed1 | speed2 | distance |
| 1 | NULL | 10 |
| 3 | NULL | 40 |
| 5 | NULL | 90 |
| NULL | 1 | 10 |
| NULL | 3 | 40 |
| NULL | 5 | 90 |
Here is the query structure (I didn't include the actual query since it's too big):
-- First group
queryForSpeed1
queryToUpdateDistanceBasedOnSpeed1
-- Second group
queryForSpeed2
queryToUpdateDistanceBasedOnSpeed2
If I run the first group of queries (queryForSpeed1 and queryToUpdateDistanceBasedOnSpeed1) separately from the second group then I get the expected output: only the speed1 and distance columns contain data:
___________________________________
| speed1 | speed2 | distance |
| 1 | NULL | 10 |
| 3 | NULL | 40 |
| 5 | NULL | 90 |
| NULL | NULL | NULL |
| NULL | NULL | NULL |
| NULL | NULL | NULL |
The same happens when I run the second group:
___________________________________
| speed1 | speed2 | distance |
| NULL | NULL | NULL |
| NULL | NULL | NULL |
| NULL | NULL | NULL |
| NULL | 1 | 10 |
| NULL | 2 | 40 |
| NULL | 3 | 90 |
BUT, when I run both groups: all the distances are NULL:
___________________________________
| speed1 | speed2 | distance |
| 1 | NULL | NULL |
| 3 | NULL | NULL |
| 5 | NULL | NULL |
| NULL | 1 | NULL |
| NULL | 2 | NULL |
| NULL | 3 | NULL |
I believe this is somehow related to transaction management and temporary tables, although I wasn't able to find anything relevant to solve the problem on Google.
From what I've read, SQL Server keeps a transaction log where it stores every update, insert and whatever... when it arrives at the end of the script it actually does all those insertions and updates.
So the update I did for the distance column finds all the speeds as being NULL because the data wasn't yet inserted in the temporary table from the previous updates, but at the end of the query the speeds are inserted in the table so that's why they are visible.
I played a bit with the GO statement to execute my script in batches, but no luck so far...
What am I doing wrong? Can someone point me in the right direction, please?
EDIT
Here is the actual query.
The problem is not related to transactions, but rather to the way you conduct updates to #temp_speed_profile. The second pass through #temp_speed_profile retrieves all six records. Speed_new is null in first record of Voyage_Id, consequently #distance becomes null. As you retain the value of #distance in next turn, it remains null.
Problem goes away when using different temporary tables because second pass works on second set of data only.
A note on cursors - when defining one make sure to add local and fast_forward. Local because it is limiting cursors' scope, and fast_forward to optimize fetches.
It is almost certainly caused by the way you have written your queries.
To confirm, just rewrite your queries using #temp_data1 and #temp_data2, rather than a single table #temp_data.
Given a table like below, is there a single-query way to update the table from this:
| id | type_id | created_at | sequence |
|----|---------|------------|----------|
| 1 | 1 | 2010-04-26 | NULL |
| 2 | 1 | 2010-04-27 | NULL |
| 3 | 2 | 2010-04-28 | NULL |
| 4 | 3 | 2010-04-28 | NULL |
To this (note that created_at is used for ordering, and sequence is "grouped" by type_id):
| id | type_id | created_at | sequence |
|----|---------|------------|----------|
| 1 | 1 | 2010-04-26 | 1 |
| 2 | 1 | 2010-04-27 | 2 |
| 3 | 2 | 2010-04-28 | 1 |
| 4 | 3 | 2010-04-28 | 1 |
I've seen some code before that used an # variable like the following, that I thought might work:
SET #seq = 0;
UPDATE `log` SET `sequence` = #seq := #seq + 1
ORDER BY `created_at`;
But that obviously doesn't reset the sequence to 1 for each type_id.
If there's no single-query way to do this, what's the most efficient way?
Data in this table may be deleted, so I'm planning to run a stored procedure after the user is done editing to re-sequence the table.
You can use another variable storing the previous type_id (#type_id). The query is ordered by type_id, so whenever there is a change in type_id, sequence has to be reset to 1 again.
Set #seq = 0;
Set #type_id = -1;
Update `log`
Set `sequence` = If(#type_id=(#type_id:=`type_id`), (#seq:=#seq+1), (#seq:=1))
Order By `type_id`, `created_at`;
I don't know MySQL very well, but you could use a sub query though it may be very slow.
UPDATE 'log' set 'sequence' = (
select count(*) from 'log' as log2
where log2.type_id = log.type_id and
log2.created_at < log.created_at) + 1
You'll get duplicate sequences, though, if two type_ids have the same created_at date.