So I have a table with 2 columns
class_id | title
CS124 | computer tactics
CS101 | intro to computers
MATH157 | math stuff
CS234 | other CS stuff
FRENCH50 | TATICS of french
ENGR101 | engineering ETHICS
OTHER1 | other CS title
I want to do a sort of smart search for auto complete where a user searches for something.
Lets say they type 'CS' into the box I want to search using both the class_id and title with a limit of lets say 5 for this example. I first want to search for class_ids like 'CS%' with a limit of 5 ordered by class_id. This will return the 3 cs classes.
Then if there is any room left in the limit I want to search using title like '%CS% and combine them but have the class_id matches be first, and make sure that duplicates are removed from the bottom like like cs234 where it would match on both queries.
So the end result for this query would be
CS101 | intro to computers
CS124 | computer tactics
CS234 | other CS stuff
ENGR101 | engineering ETHICS
FRENCH50 | TATICS of french
I am trying to do something like this
(select * from class_infos
where LOWER(class_id) like LOWER('CS%')
order by class_id)
union
(select * from class_infos
where LOWER(title) like LOWER('%CS%')
order by class_id)
limit 30
But it is not putting them in the right order or make the class id query have priority. Anyone have any suggestions
Here is the sqlfiddle
http://sqlfiddle.com/#!15/5368b
Have you try something like this?
SQL Fiddle Demo
SELECT *
FROM
(
(select 1 as priority, *
from class_infos
where LOWER(class_id) like LOWER('CS%'))
union
(select 2 as priority, *
from class_infos
where
LOWER(title) like LOWER('%CS%')
and not LOWER(class_id) like LOWER('CS%')
)
) as class
ORDER BY priority, class_id
limit 5
Related
I want in the output a hierarchical order like so:
My Data :
Name | Cost | Level
----------------+--------+------
Car1 | 2000 | 1
Component1.1 | 3000 | 2
Component1.2 | 2300 | 3
Computer2 | 5000 | 1
Component2.1 | 2000 | 2
Component2.2 | Null | 3
Output: Show all those data, which has money in it and order it by the level, something like first 1, then 2, then,3 and after that start with 1 again.
Name | Level
------------------+------
Car1 | 1
Component1.1 | 2
Component1.2 | 3
Computer | 1
Component2.1 | 2
What ORDER BY does is:
Name | Level
----------------+------
Car1 | 1
Computer1 | 1
Component1.1 | 2
Component2.1 | 2
Component1.2 | 3
Component2.2 | 3
I tried the CONNECT BY PRIOR function and it didn't work well
SELECT Name, Level
FROM Product
CONNECT BY PRIOR Level;
In MySQL you would normaly use 'order by'. So if you want to order on table row "level" your synntax would be something like this:
SELECT * FROM items ORDER BY level ASC
You can make use of ASC (Ascending) or DESC (descending).
Hope this will help you.
You can use below one
SELECT Name, Level
FROM Auction
ORDER BY Name, Level
WHERE Money!='Null' ;
Doing order by Name will print the result in hierarchical order, but if it has a column called parent id, then it would have been easier to show.
i suggest this for you :
SELECT Name, Level FROM Product ORDER BY Name, Level WHERE Money!='Null' ASC;
i wish this help you brother
It is still not clear whether this is what you are really expecting. It seems to me from your data set, you want to numerically order the components based on some kind of a version number at the end of the component. If that's truly what you want then you may ignore the non-numeric characters in the name and order by pure numbers towards the end of string ( with the required where clause ).
ORDER BY REPLACE ( name, TRANSLATE(name,' .0123456789',' '),'');
If that's the case, then the adding level too to the ORDER BY shouldn't make any difference unless your numeric order of versions and level are in sync.
A problem may appear if you have components like component2_name1.2 etc which could break this logic, for which you may require REGEXP to identify the required pattern. But, it doesn't appear so from your data and I assumed that to be the case and you may want to clarify if that's not what you may always have in your dataset.
Here's a demo of the result obtained for your sample data.
Demo
This will work of the numeric character is always a valid decimal and has only one decimal point. If you have complex versioning system like say 1.1.8, 2.1.1 etc, it needs far sophisticated ordering on top of REPLACE ( name, TRANSLATE(name,' .0123456789',' '),'').
You will find such examples in posts such as this one Here
Note: I would request you to also please read the instructions here to know how to ask a good question. This would avoid all confusion to people who try to understand and answer your question.
I'm trying to implement a cursor-based paginating list based off of data from a Postgres database.
As an example, say I have a table with the following columns:
id | firstname | lastname
I want to paginate this data, which would be pretty simple if I only ever wanted to sort it by the id, but in my case, I want the option to sort by last name, and there's guaranteed to be multiple people with the same last name.
If I have a select statement like follows:
SELECT * FROM people
ORDER BY lastname ASC;
In the case, I could make my encoded cursor contain information about the lastname so I could pick up where I left off, but since there will be multiple users with the same last name, this will be buggy. Is there a way in SQL to only get the results after a certain id in an ordered list where it is not the column by which the results are sorted?
Example results from the select statement:
1 | John | Doe
4 | John | Price
2 | Joe | White
6 | Jim | White
3 | Sam | White
5 | Sally | Young
If I wanted a page size of 3, I couldn't add WHERE lastname <= :lastname as I'd have duplicate data on the list since it would return ids 2, 6, and 3 during that call. In my case, it'd be helpful if I could add to my query something similar to AFTER id = 6 where it could skip everything until it finds that id in the ordered list.
Yes. If I understand correctly:
select t.*
from t
where (lastname, id) > (select t2.lastname, t2.id
from t t2
where t2.id = ?
)
order by t.lastname;
I think I would add firstname into the mix, but it is the same idea.
Limit and offset are used for pagination e.g.:
SELECT id, lastname, firstname FROM people
Order by lastname, firstname, id
Offset 0
Limit 10
This will bring you the first to the 10th row, to retrieve the next page you need to specify the offset to 10
Here the documentation:
https://www.postgresql.org/docs/9.6/static/queries-limit.html
First of all, sorry for the title. Couldn't think of any better title.
This is what I got:
SELECT study FROM old_employee;
study
---------
STUDY1
STUDY2
STUDY3
STUDY1
STUDY2
SELECT id,name_string FROM studies;
id | name_string
----+-------------------
1 | STUDY1
2 | STUDY2
3 | STUDY3
Now I would like to find the id's based on the first output. This is what i've attempted but obviously it's not working.
SELECT id FROM studies WHERE name_string LIKE (SELECT study FROM old_employee);
My desired output:
id
----
1
2
3
1
2
edit: I'm saving old_employee as a view and i'm wondering if there's a smarter way of including it in the answers below instead of creating this view first.
CREATE VIEW old_employee AS
SELECT *
FROM dblink('dbname=mydb', 'select study from personnel')
AS t1(study char(10));
This can be accomplished without using SQL LIKE Operator. Here is the query.
SELECT s.id
FROM studies s,
old_employee o
WHERE s.name_string = o.study;
Second query (According to what #a_horse_with_no_name said):
SELECT studies.id
FROM studies
INNER JOIN old_employee
ON studies.name_string = old_employee.study
Hi stackoverflow users
I'm having a bit of a problem trying to combine SUM, MAX and WHERE in one query and after an intense Google search (my search engine skills usually don't fail me) you are my last hope to understand and fix the following issue.
My goal is to count people in a certain period of time and because a person can visit more than once in said period, I'm using MAX. Due to the fact that I'm defining people as male (m) or female (f) using a string (for statistic purposes), CHAR_LENGTH returns the numbers I'm in need of.
SELECT SUM(max_pers) AS "People"
FROM (
SELECT "guests"."id", MAX(CHAR_LENGTH("guests"."gender")) AS "max_pers"
FROM "guests"
GROUP BY "guests"."id")
So far, so good. But now, as stated before, I'd like to only count the guests which visited in a certain time interval (for statistic purposes as well).
SELECT "statistic"."id", SUM(max_pers) AS "People"
FROM (
SELECT "guests"."id", MAX(CHAR_LENGTH("guests"."gender")) AS "max_pers"
FROM "guests"
GROUP BY "guests"."id"),
"statistic", "guests"
WHERE ( "guests"."arrival" <= "statistic"."from" AND "guests"."departure" >= "statistic"."to")
GROUP BY "statistic"."id"
This query returns the following, x = desired result:
x * (x+1)
So if the result should be 3, it's 12. If it should be 5, it's 30 etc.
I probably could solve this algebraic but I'd rather understand what I'm doing wrong and learn from it.
Thanks in advance and I'm certainly going to answer all further questions.
PS: I'm using LibreOffice Base.
EDIT: An example
guests table:
ID | arrival | departure | gender |
10 | 1.1.14 | 10.1.14 | mf |
10 | 15.1.14 | 17.1.14 | m |
11 | 5.1.14 | 6.1.14 | m |
12 | 10.2.14 | 24.2.14 | f |
13 | 27.2.14 | 28.2.14 | mmmmmf |
statistic table:
ID | from | to | name |
1 | 1.1.14 | 31.1.14 |January | expected result: 3
2 | 1.2.14 | 28.2.14 |February| expected result: 7
MAX(...) is the wrong function: You want COUNT(DISTINCT ...).
Add proper join syntax, simplify (and remove unnecessary quotes) and this should work:
SELECT s.id, COUNT(DISTINCT g.id) AS People
FROM statistic s
LEFT JOIN guests g ON g.arrival <= s."from" AND g.departure >= s."too"
GROUP BY s.id
Note: Using LEFT join means you'll get a result of zero for statistics ids that have no guests. If you would rather no row at all, remove the LEFT keyword.
You have a very strange data structure. In any case, I think you want:
SELECT s.id, sum(numpersons) AS People
FROM (select g.id, max(char_length(g.gender)) as numpersons
from guests g join
statistic s
on g.arrival <= s."from" AND g.departure >= s."too"
group by g.id
) g join
GROUP BY s.id;
Thanks for all your inputs. I wasn't familiar with JOIN but it was necessary to solve my problem.
Since my databank is designed in german, I made quite the big mistake while translating it and I'm sorry if this caused confusion.
Selecting guests.id and later on grouping by guests.id wouldn't make any sense since the id is unique. What I actually wanted to do is select and group the guests.adr_id which links a visiting guest to an adress databank.
The correct solution to my problem is the following code:
SELECT statname, SUM (numpers) FROM (
SELECT statistic.name AS statname, guests.adr_id, MAX( CHAR_LENGTH( guests.gender ) ) AS numpers
FROM guests
JOIN statistics ON (guests.arrival <= statistics.too AND guests.departure >= statistics.from )
GROUP BY guests.adr_id, statistic.name )
GROUP BY statname
I also noted that my database structure is a mess but I created it learning by doing and haven't found any time to rewrite it yet. Next time posting, I'll try better.
I have a rails 3.2 app running on PostgreSQL, and have some data I want to display in my view, which is stored in the database in this structure:
+----+--------+------------------+--------------------+
| id | name | sched_start_date | task |
+----+--------+------------------+--------------------+
| 1 | "Ben" | 2013-03-01 | "Check for debris" |
+----+--------+------------------+--------------------+
| 2 | "Toby" | 2013-03-02 | "Carry out Y1.1" |
+----+--------+------------------+--------------------+
| 3 | "Toby" | 2013-03-03 | "Check oil seals" |
+----+--------+------------------+--------------------+
I would like to display a list of tasks for each name, and for the names to be ordered ASC by the first sched_start_date they have, which should look like ...
Ben
2013-03-01 – Check for debris
Toby
2013-03-02 – Carry out Y1.1
2013-03-03 – Check oil seals
The approach I starting taking was to run a query for unique names and order them by sched_start_date ASC, then run a query for each name to get their tasks.
To get a list of unique names, the SQL would look like this.
select *
from (
select distinct on (name) name, sched_start_date
from tasks
) p
order by sched_start_date;
I would like to know if this is the correct approach (querying for unique names then running another query for all their tasks), or if there is a better rails way.
To get the data sorted like you describe, you might want to use min() as window function in the ORDER BY clause:
SELECT name, sched_start_date, task
FROM tasks
ORDER BY min(sched_start_date) OVER (PARTITION BY name), 1, 2, 3
Your original query would need an additional ORDER BY item to get the earliest date per name:
SELECT DISTINCT ON (name) name, sched_start_date, task
FROM tasks
ORDER BY 1, 2, 3;
I also added task (3) as last ORDER BY item to break ties, in case there can be more than one per date.
But the output is still ordered by name, not by date.
Getting your peculiar format with all data stuffed into one column is a bit more complex:
SELECT one_col
FROM (
WITH x AS (
SELECT name, min(sched_start_date) AS min_start
FROM tasks
GROUP BY 1
)
SELECT 2 AS rnk, name
,sched_start_date::text || ' – ' || task AS one_col
,sched_start_date, min_start
FROM tasks
JOIN x USING (name)
UNION ALL
SELECT 1 AS rnk, name, name, NULL::date, min_start
FROM x
ORDER BY min_start, name, rnk, sched_start_date, task
) y
Assuming that you have associations in your model you would be able to run
#employees = Employee.order(:name, :sched_start_date, :task).includes(:tasks)
You could then iterate over them:
#employees.each do |employee|
employee.name
employee.tasks.each do |task|
task.name
end
end
This isn't gonna exactly match your needs, but should show you where to start.