I have a sp result like,
subject | Chapter no. | marks
English 1 99
English 2 99
English 3 99
Science 1 100
Science 2 100
This sp result is based on subject, each subject may have different chapterno. but the marks are based on the subject. So I have to avoid the duplication to avoid error while calculating the total marks.
Hence I need this like,
subject | Chapter no. | marks
English 1 99
English 2 0/null
English 3 0/null
Science 1 100
Science 2 0/null
Please guide me to solve this.
You can try like this:
SELECT MIN([Chapter no.]) AS col, subject
FROM yourTable
GROUP BY subject
Related
I'm ranking race data for series of cycling events. Racers win various amounts of points for their position in races. I want to retain the discrete event scoring, but also rank the racer in the series. For example, considering a sub-query that returns this:
License #
Rider Name
Total Points
Race Points
Race ID
123
Joe
25
5
567
123
Joe
25
12
234
123
Joe
25
8
987
456
Ahmed
20
12
567
456
Ahmed
20
8
234
You can see Joe has 25 points, as he won 5, 12, and 8 points in three races. Ahmed has 20 points, as he won 12 and 8 points in two races.
Now for the ranking, what I'd like is:
Place
License #
Rider Name
Total Points
Race Points
Race ID
1
123
Joe
25
5
567
1
123
Joe
25
12
234
1
123
Joe
25
8
987
2
456
Ahmed
20
12
567
2
456
Ahmed
20
8
234
But if I use rank() and order by "Total Points", I get:
Place
License #
Rider Name
Total Points
Race Points
Race ID
1
123
Joe
25
5
567
1
123
Joe
25
12
234
1
123
Joe
25
8
987
4
456
Ahmed
20
12
567
4
456
Ahmed
20
8
234
Which makes sense, since there are three "ties" at 25 points.
dense_rank() solves this problem, but if there are legitimate ties across different racers, I want there to be gaps in the rank (e.g if Joe and Ahmed both had 25 points, the next racer would be in third place, not second).
The easiest way to solve this I think would be to issue two queries, one with the "duplicate" racers eliminated, and then a second one where I can retain the individual race data, which I need for the points break down display.
I can also probably, given enough effort, think of a way to do this in a single query, but I'm wondering if I'm not just missing something really obvious that could accomplish this in a single, relatively simple query.
Any suggestions?
You have to break this into steps to get what you want, but that can be done in a single query with common table expressions:
with riders as ( -- get individual riders
select distinct license, rider, total_points
from racists
), places as ( -- calculate non-dense rankings
select license, rider, rank() over (order by total_points desc) as place
from riders
)
select p.place, r.* -- join rankings into main table
from places p
join racists r on (r.license, r.rider) = (p.license, p.rider);
db<>fiddle here
Students table
student_id student_name
1 John
2 Mary
Grades table
student_id year grade_level school Course Mark
1 2015 10 Smith High Algebra 95
1 2015 10 Smith High English 96
1 2016 11 Smith High Geometry 85
1 2016 11 Smith High Science 88
2 2015 10 Smith High Algebra 98
2 2015 10 Smith High English 93
2 2016 11 Smith High Geometry 97
2 2016 11 Smith High Science 86
I'm trying to show results for each year and what class a student took with the grade.
So the final output i'm looking for is something like:
[student_id1] [year1] [grade1] [school1]
[course1] [mark1]
[course2] [mark2]
[course3] [mark3]...
[student_id1] [year2] [grade2] [school1]
[course1] [mark1]
[course2] [mark2]
[course3] [mark3]...
[student_id2] [year1] [grade1] [school1]
[course1] [mark1]
[course2] [mark2]
[course3] [mark3]...
This would all go in one column/row. So in this particular example, this would be my result:
1 2015 10 Smith High
Algebra 95
English 96
1 2016 11 Smith High
Geometry 85
Science 88
2 2015 10 Smith High
Algebra 98
English 93
2 2016 11 Smith High
Geometry 97
Science 86
So anytime a student id, year, grade, or school name changes, I would have a line for that and loop through the classes taken within that group. And all of this would be in one column/row.
This is what I have so far but I'm not sure how I can properly loop through course and grades for each group. I'd appreciate it if I can be pointed in the right direction.
select s.student_id + '' + year + '' + grade_level + '' + school
from students
join grades on students.student_id = grades.student_id
If you want to do it in your SQL Enviromnment, it depends on the Database Management System you are using.
For example, if you are using Transact SQL you can try to look at this link.
Generally this kind of loops and interactions are done in the programming language that is coupled with the SQL DB.
Anyway, you should look at Stored Procedures and Cursors if you really want to do this in SQL.
You are trying to mix presentation with retrieval of data from database tables. Looping through the resultset in sql can be achieved via cursor but that isn't adviced. You are better off by pulling the required data using two queries and later print it using a language of your choice.
how do i join following tables with wildcards? I would like to get all distinct rows from People table which contains SearchedName from SearchedPeople table.
SearchedPeople:
SearchedName
--------
Andrew
John
John Smith
People:
ID PersonName Attribute Age
----------------------------------------
1 John Smith 1 23
2 John Smith Jr 3 25
3 John Smith Jr II 4 73
4 Kevin 2 21
5 Andrew Smith 1 14
6 Marco 5 90
Desired Output:
PersonName Attribute Age
----------------------------------------
John Smith 1 23
John Smith Jr 3 25
John Smith Jr II 4 73
Andrew Smith 1 14
Code i got so far which doesnt wor. It returns three empty rows(why is that?).
SELECT b.PersonName, b.Attribute, b.Age
FROM SearchedPeople a
LEFT JOIN People b ON "%"&a.SearchedName&"%" like b.PersonName
It returns three empty rows because you don't have any columns from table a (SearchedPeople) and the LEFT JOIN didn't produce a match.
The reason is your criteria is in the wrong order you are searching for PersonName in the string %Searchedname% you need to switch that around. Also Access doesn't like the % as much as it likes the asteriks * for wilcard unless you make some changes to the query or configuration of MS-Access see below comment from Parafait.
I just tested this:
SELECT a.SearchedName
,b.PersonName, b.Attribute, b.Age
FROM
SearchedPeople a
LEFT JOIN People b
ON b.PersonName LIKE ("*" & a.SearchedName & "*")
Edit:
Good Ms Access specific information from a comment from #Parafait pasting in answer in case comment every got deleted.:
Use ALIKE and percents work. And if OP connects to MS Access via OLEDB and not the GUI .exe program, the % operator is required for LIKE statements in coded SQL. OP can also change database settings to ANSI-92 mode to always use % wildcards.
For examples I have this access table
fruit person price
apple jhon 5
apple mary 12
pear alison 10
grape kim 12
grape kim 24
grape jack 9
How we can count fruit and added another fields(couNum) like that ?
couNum fruit person price
1 apple jhon 5
2 apple mary 12
1 pear alison 10
1 grape kim 12
2 grape kim 24
3 grape jack 9
Please help thanks.
This is painful to do in MS Access, but you can do it with a subquery -- assuming that you have a unique column for each row:
select t.*,
(select count(*)
from t as t2
where t2.fruit = t.fruit and t2.person <= t.person
) as couNum
from t;
In most other databases, you would simply use row_number(). If you are learning SQL and have a choice on what database to use, I would steer you to one of the more "up-to-date" databases such as Postgres, MySQL, SQL Server, Oracle, or almost anything else.
Say I have an employee table, with a record for each employee in my company, and a column for supervisor (as seen below). I would like to prepare a report, which lists the names and title for each step in a supervision line. eg for dick robbins, 1d #15, i'd like a list of each supervisor in his "chain of command," all the way to the president, big cheese. I'd like to avoid using cursors, but if that's the only way to do this then that's ok.
id fname lname title supervisorid
1 big cheese president 1
2 jim william vice president 1
3 sally carr vice president 1
4 ryan allan senior manager 2
5 mike miller manager 4
6 bill bryan manager 4
7 cathy maddy foreman 5
8 sean johnson senior mechanic 7
9 andrew koll senior mechanic 7
10 sarah ryans mechanic 8
11 dana bond mechanic 9
12 chris mcall technician 10
13 hannah ryans technician 10
14 matthew miller technician 11
15 dick robbins technician 11
The real data probably won't be more than 10 levels deep...but I'd rather not just do 10 outside joins...I was hoping there was something better than that, and less involved than cursors.
Thanks for any help.
This is basically a port of the accepted answer on my question that I linked to in the OP comments.
you can use common-table expressions
WITH Family As
(
SELECT e.id, e.supervisorid, 0 as Depth
FROM Employee e
WHERE id = #SupervisorID
UNION All
SELECT e2.ID, e2.supervisorid, Depth + 1
FROM Employee e2
JOIN Family
On Family.id = e2.supervisorid
)
SELECT*
FROM Family
For more:
Recursive Queries Using Common Table Expressions
You might be interested in the "Materialized Path" solution, which does slightly de-normalize the table but can be used on any type of SQL database and prevents you from having to do recursive queries. In fact, it can even be used on no-SQL databases.
You just need to add a column which holds the entire ancestry of the object. For example, the table below includes a column named tree_path:
+----+-----------+----------+----------+
| id | value | parent | tree_path|
+----+-----------+----------+----------+
| 1 | Some Text | 0 | |
| 2 | Some Text | 0 | |
| 3 | Some Text | 2 | -2-|
| 4 | Some Text | 2 | -2-|
| 5 | Some Text | 3 | -2-3-|
| 6 | Some Text | 3 | -2-3-|
| 7 | Some Text | 1 | -1-|
+----+-----------+----------+----------+
Selecting all the descendants of the record with id=2 looks like this:
SELECT * FROM comment_table WHERE tree_path LIKE '-2-%' ORDER BY tree_path ASC
To build a tree, you can sort by tree_path to get an array that's fairly easy to convert to a tree.
You can also index tree_path and the index can be used when the wildcard is not at the beginning.
For example, tree_path LIKE '-2-%' can use the index, but tree_path LIKE '%-2-' cannot.
Some recursive function which either return the supervisor (if any) or null. Could be a SP which invokes itself as well, and using UNION.
SQL is a language for performing set operations and recursion is not one of them. Further, many database systems have limitations on recursion using stored procedures as a safety measure to prevent rogue code from running away with precious server resources.
So, when working with SQL always think 'flat', not 'hierarchical'. So I would highly recommend the 'tree_path' method that has been suggested. I have used the same approach and it works wonderfully and crucially, very robustly.