How can I create a column that has ranked the information of the table based on two or three keys?
For example, in this table the rank variable is based on Department and Name:
Dep | Name | Rank
----+------+------
1 | Jeff | 1
1 | Jeff | 2
1 | Paul | 1
2 | Nick | 1
2 | Nick | 2
I have found this solution but it's in SQL and I don't think it applies to my case as all information is in one table and the responses seem to SELECT and JOIN combine information from different tables.
Thank you in advance
You can count how many rows come before the current row in the current group:
UPDATE MyTable
SET Rank = (SELECT COUNT(*)
FROM MyTable AS T2
WHERE T2.Dep = MyTable.Dep
AND T2.Name = MyTable.Name
AND T2.rowid <= MyTable.rowid);
(The rowid column is used to differentiate between otherwise identical rows. Use the primary key, if you have one.)
Related
I'm trying to get one row from table that have an id column that duplicate in several rows of a SQlite database, but I am getting all rows in table.
This is my table creation and selection query.
CREATE TABLE IMAGES ( MID INTEGER , IMAGE BLOB, ID INTEGER );
SELECT DISTINCT ID, IMAGE FROM IMAGES;
This what I get
mid | image | id
1 | m1 | 1
2 | m2 | 1
3 | m3 | 1
4 | m4 | 2
5 | m5 | 3
6 | m6 | 3
And this what i want
mid | image | id
1 | m1 | 1
4 | m4 | 2
5 | m5 | 3
DISTINCT applies to all the SELECTed columns, i.e., you get each unique combination of id and image in the data.
To control which columns get deduplicated, use GROUP BY.
You also have to specify which image you want for each ID; if you don't use MIN(), you get a random image:
SELECT id, MIN(image)
FROM images
GROUP BY id;
You need to choose the correct columns
SELECT min(mid) FROM images GROUP BY id;
Then you need to use that to select the correct rows.
SELECT DISTINCT ID, IMAGE FROM IMAGES WHERE mid in (SELECT min(mid) FROM images GROUP BY id);
Otherwise the records from the GROUP BY, could be made up from any (or last) of the rows.
I have a query result set like this:
value | id
500 | 1
400 | 1
300 | 2
and a product table:
product_name | id
product_1 | 1
product_2 | 2
product_5 | 3
product_6 | 4
product_9 | 5
product_0 | 6
Now I want to find the product_name from product table for every row in query result set and join the result to look like following:
The result after joining should be following:
product_name | id | value
product_1 | 1 | 500
product_1 | 1 | 400
product_2 | 2 | 300
I am getting confused how to use left join to achieve the result.
You'd join based on the value that's common between the two tables; in this case, it's id.
It doesn't seem like you want any NULL values for value, so you wouldn't use a LEFT JOIN; you'd want an INNER JOIN instead.
This would get you pretty much what you want; bear in mind that this is untested.
SELECT p.product_name, qr.id, value
FROM product p
INNER JOIN query_result_set qr ON qr.id = p.id
ORDER BY value DESC;
Also, your expectations are wrong - product_5 has an id of 3, so it wouldn't appear in this join result.
I have table [Surgery_By] table[Surgery] table[Doctor] i'm using ASP.NET with SQL Server :
The table [Surgery_By] contains the following columns:
1-ID (PK)
2-Surgery ID (FK)
3-Doctor ID (FK)
How to Display doctors ordered by number of performed surgeries ?
Try it this way
SELECT d.id, d.fullname, COUNT(s.id) total_surgeries
FROM doctor d LEFT JOIN surgery_by s
ON d.id = s.doctor_id
GROUP BY d.id, d.fullname
ORDER BY total_surgeries DESC
Sample output:
| ID | FULLNAME | TOTAL_SURGERIES |
|----|------------|-----------------|
| 1 | John Doe | 3 |
| 2 | Jane Doe | 1 |
| 3 | Mark Smith | 0 |
Here is SQLFiddle demo
This is a stab in the dark.
Select Doctor.ID As DoctorID
,Count(*) As Count
From Doctor
Join Surgery_By
On Doctor.ID = Surgery_By.DoctorID
Group By Doctor.DoctorID
Order By Count(*)
I am not sure if you want the table Surgery incorporated (but if you do, the join will be pretty straight forward - just be sure to add selected columns to the Group By statement.)
From ASP.NET, you may select this data from a SQL Command.
I have a table with this structure:
id | IDs | Name | Type
1 | 10 | A | 1
2 | 11 | B | 1
3 | 12 | C | 2
4 | 13 | D | 3
except id nothing else is a FOREIGN or PRIMARY KEY. I want to select a row based on it's column values that are not PRIMARY KEY. I have tried the following syntax but it yields no results.
SELECT * FROM MyTable WHERE Name = 'A', Type = 1;
what am I doing wrong? What is exactly returned by a SELECT statement? I'm totally new to Data Base and I'm currently experimenting and trying to learn it. so far my search has not yield any results regarding this case.
Use and to add multiple conditions to your query
SELECT *
FROM MyTable
WHERE Name = 'A'
AND Type = 1;
I have A table and two rows with id=1 and id=2 and their x parameter is 1. I also have B table and two rows with same id 1 and 2. I am trying to update all of the data(column)on B table which has same id with A table whose x parameter is 1.
A table
id | x |
1 | 1 |
2 | 1 |
B table
id | Y |
1 | yes|
2 | yes|
My query is
UPDATE B SET y='No' WHERE B.id=(SELECT A.id FROM A WHERE A.x=1);
The problem is select returns mutliple data and i can only update the first data.
I tried to use JOIN but sqlite gives syntax error near INNER i couldn't find the problem.
UPDATE B SET B.y='No' INNER JOIN A ON B.id=A.id WHERE A.x=1;
Use this:
UPDATE ... WHERE B.id IN (SELECT A.id ...);