I've created a query in Postgres which is limiting the number of results but for some reason, my limit clause is showing one less result that I ask for. Here is the query:
select articles.title, articles.slug, count.views
from articles,
(select path, count(path) as views
from log
where status = '200 OK'
and path != '/'
group by path
order by views desc limit 3
) count
WHERE articles.slug LIKE LTRIM(count.path, '/article/');
but when I run it, I only get the first 2 rows. If I change the 3 to 4, I get the first 3 rows and so on. Any suggestions?
When I remove the limit, all 6 relevant rows are displayed and if I use limit 3 offset 1 in returns the top 3 rows as requested so I believe the Gordon's answer is correct. – Gerry de Caires
Related
Here's an example:
ID = INT IDENTITY
DESC = VARCHAR(5000)
ID | Desc
---|-----
1 | a
2 | aaa
3 | aa
The SQL query here should return 3 and the word itself i.e., aaa? Since the longest value is aaa with 3 characters?
The output should be:
aaa 3
You can use order by and limit the results to one row:
select description, len(description)
from t
order by len(description) desc
offset 0 row fetch first 1 row only;
Or use:
select top (1) description, len(description)
from t
order by len(description) desc;
With OFFSET & FETCH:
OFFSET is specifying how many rows from the top of the result set you will ignore ...
And then the FETCH is used to limit the result to the number of rows you specify.
The combination of this two will return the desired result because the result set is ordered by len(descr).
select descr, len(descr)
from test
order by len(descr) desc
OFFSET 0 ROWS
fetch first 1 rows only;
With TOP:
TOP will limit the reultset to the number of rows you specify. In this example 1. Because it is ordered by the lenght of the column desc then the first row will be the one you are looking for.
select top 1 descr, len(descr)
from test
order by len(descr) desc
HERE IS A DEMO for both examples
Note for the end:
Use aliases (I will demonstrate on one of this two examples)
select descr as Description, len(descr) "Description length"
from test
order by len(descr) desc
OFFSET 0 ROWS
fetch first 1 rows only;
You can put them between double quotes or not, use keyword as or not, it is up to you but the result looks better with them.
Both ROW and ROWS keyword is ok for OFFSET and FETCH clause. So what ever you want to use you can...
You can try TOP as shown below. Here is the official documentation of TOP (Transact-SQL).
Select
top 1 Id, description, len(description) as MaxLength
from YourTable order by len(description) desc
Live Demo
This will do what you want on Oracle (one of the tags on the question):
SELECT descript,length(descript)
FROM t WHERE length(descript)=( SELECT max(length(descript)) FROM t);
Keep in mind that if there are two (or more) records with that length, you will get them all. You could add a AND rownum < 2 clause but that will give you which ever entry the database chooses to give.
If you want the first record of those with the longest field, a subquery will be required:
SELECT descript,length(descript) from (
select descript from t order by length(descript) desc, descript asc)
WHERE rownum < 2;
There is also the offset 0 row fetch... version listed earlier:
SQL> select descript, length(descript)
2 from t
3 order by length(descript) desc
4 offset 0 row fetch first 1 row only;
DESCRIPT LENGTH(DESCRIPT)
-------------------- ----------------
defg 4
Mind you, this only works on my "12.2.0.1.0" Oracle. If I try the same thing on my "11.2.0.4.0" Oracle, I get "ORA-00933: SQL command not properly ended" with that last line. Apparently this is newer, maybe that is why I have never seen it before.
I just joined after having a problem writing a query in MS Access. I am trying to write a query that will pull out the first two valid samples in from a list of replicated sample results and then would like to average the sample values. I have written a query that does pull samples with only two valid samples and averages these values. However, my query doesn't pull samples where there are more than two valid sample results. Here's my query:
SELECT temp_platevalid_table.samp_name AS samp_name, avg (temp_platevalid_table.mean_conc) AS fin_avg, count(temp_platevalid_table.samp_valid) AS sample_count
FROM Temp_PlateValid_table
WHERE (Temp_PlateValid_table.id In (SELECT TOP 2 S.id
FROM Temp_PlateValid_table as S
WHERE S.samp_name = S.samp_name and s.samp_valid=1 and S.samp_valid=1
ORDER BY ID))
GROUP BY Temp_PlateValid_table.samp_name
HAVING ((Count(Temp_PlateValid_table.samp_valid))=2)
ORDER BY Temp_PlateValid_table.samp_name;
Here's an example of what I'm trying to do:
ID Samp_Name Samp_Valid Mean_Conc
1 54d2d2 1 15
2 54d2d2 1 20
3 54d2d2 1 25
The average mean_conc should be 17.5, however, with my current query, I wouldn't receive a value at all for 54d2d2. Is there a way to tweak my query so that I get a value for samples that have more than two valid values? Please note that I'm using MS Access, so I don't think I can use fancier SQL code (partition by, etc.).
Thanks in advance for your help!
Is this what you want?
select pv.samp_name, avg(pv.value_conc)
from Temp_PlateValid_table pv
where pv.samp_valid = 1 and
pv.id in (select top 2 id
from Temp_PlateValid_table as pv2
where pv2.samp_name = pv.samp_name and pv2.samp_valid = 1
)
group by pv.samp_name;
You might need avg(pv.value_conc * 1.0).
I don't know what's going on with my code here. I am trying to return the highest number of calls received by particular phone numbers, and find the top 7 numbers by calls received, but I am only getting the count column in my results. The code is:
SELECT COUNT (call_id) FROM call_test
GROUP BY receiver_id
ORDER BY COUNT(call_id) DESC
LIMIT 7;
But all it is returning is:
COUNT(call_id)
3
2
2
2
2
1
1
I think my code is right, but how do you show the particular numbers that correspond to the respective counts? This is SQLPro for MAC.
Is it as simple as including the number in the select?
SELECT receiver_id, COUNT(call_id)
FROM call_test
GROUP BY receiver_id
ORDER BY COUNT(call_id) DESC
LIMIT 7;
See the below example,
create table data(name varchar, value int);
insert into data values('joe',1);
insert into data values('bob',2);
insert into data values('jane',3);
insert into data values('anne',4);
insert into data values('kate',5);
And if I Execute
select * from data limit 2;
Will Get
name | value
------+-------
joe | 1
bob | 2
(2 rows)
So,How Can I Get the Last 2 Rows in select * from data?
What I'm expecting is....
name | value
------+-------
anne | 4
kate | 5
(2 rows)
You have two options according to your need i.e,
select * from data order by value desc limit 2
Or
LIMIT and OFFSET
if you want the 4th and 5th row just offset the first 3 so that the 4th row becomes the start of our set and you can specify a limit to say that you only want 2 rows from that.
select * from data offset 3 limit 2;
/* The order of LIMIT and OFFSET does not matter. This gives the same result */
select * from data limit 2 offset 3;
I know I'm answering a six year old question and I know the accepted answer says to use an offset, however that's only going to be useful if you know the length of the table. Looking at the wording of the question and the example given, I assumed that like myself, the author wanted the last entries in a table based on an id or other value in the order that they were entered.
The best solution I've found so far that orders the values as expected is using a subquery as follows:
SELECT * FROM ( SELECT * FROM data ORDER BY VALUE DESC LIMIT 2) AS _ ORDER BY VALUE ASC;
You'd substitute VALUE for whichever column you'd want to sort by to get the "last" entries. In my experience, this method is an order of magnitude quicker than using a count to find an offset.
To get the x last rows, example with x=10,
use offset alone, with count:
SELECT *
FROM data
ORDER BY value ASC
OFFSET (SELECT count(*) FROM DATA)-10
I let you check if the offset is not negative...
Make use of Order by Clause
select * from data order by value desc limit 2;
OR
select top 2 * from data order by value desc ;
You can achieve it using Order by clause desc
SELECT *
FROM data
ORDER BY value DESC limit 2;
like does Krishraj Rana you can try this function for get the last row with "limit 1" and order by "x col" desc, complete it "by x_col desc limit 1".
I want to select the top N rows of a table, ranked by how high the number in one of their columns is.
I already have:
SELECT * FROM movie ORDER BY worldwide_gross DESC;
How can I get the first twenty?
If it makes any difference I'm using MySQL.
Cheers!
Definition: Limit is used to limit your MySQL query results to those that fall within a specified range. You can use it to show the first X number of results, or to show a range from X - Y results. It is phrased as Limit X, Y and included at the end of your query. X is the starting point (remember the first record is 0) and Y is the duration (how many records to display).
Also Known As: Range Results
Examples:
SELECT * FROM `your_table` LIMIT 0, 10
This will display the first 10 results from the database.
SELECT * FROM `your_table` LIMIT 5, 5
This will show records 6, 7, 8, 9, and 10
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I believe:
SELECT *
FROM movie
ORDER BY worldwide_gross DESC
LIMIT 20
should do the trick. See also this link.