How I can get min difference between two integer fields(value_0 - value)?
value_0 >= value always
value_0 | value
-------------------
15 | 10
12 | 10
15 | 11
11 | 11
Try this:
SELECT MIN(value_0-value) as MinDiff
FROM TableName
WHERE value_0>=value
With the sample data you have given,
Output is 0. (11-11)
See demo in SQL Fiddle.
Read more about MIN() here.
Here is one way:
select min(value_0 - value)
from table t;
This is pretty basic SQL. If you want to see other values on the same row as the minimum, use order by and choose one row:
select (value_0 - value)
from table t
order by (value_0 - value)
limit 1;
The limit 1 works in some databases for getting one row. Others use top 1 in the select clause. Or fetch first 1 rows only. Or even something else.
Related
I'd like to create a query that returns a column with a repeating number sequence in it.
For example:
row_num | repeat
----------------
1 | 1
2 | 2
3 | 3
4 | 1
5 | 2
6 | 3
I'm struggling to understand how I could achieve this with BigQuery Standard SQL.
So far i've generated the row number (ROW_NUMBER() OVER()) as row_num in my select, and then I was thinking I could use a modulus function to determine the repeat number, but this would split it into several separate columns, so I'd need additional steps to merge them into the one column. I wondered if there was a more elegant way of achieving this.
Many Thanks!
In fact, the modulus should work here. Assuming your table already has a row_num column, and you want to generate the repeat column, you may try:
SELECT
row_num,
MOD(row_num - 1, 3) + 1 AS repeat
FROM yourTable
ORDER BY
row_num;
Can you help me with sql query to get the desired result
Database used :- Redshift
requirement is
I have 3 columns as:- dish_id,cateogory_id,counter
So i want counter to increase +1 if the dish_id is repeated and if not it should remain 1
the query i need should be able to query the source table and get the results as
dish_id category_id counter
21 4 1
21 6 2
21 6 3
12 1 1
Unless I missunderstood your question, you can accomplish that using window functions:
SELECT *,row_number() OVER (PARTITION BY dish_id) FROM my_table;
I am trying to sort the numbers,
MH/122020/101
MH/122020/2
MH/122020/145
MH/122020/12
How can I sort these in an Access query?
I tried format(mid(first(P.PFAccNo),11),"0") but it didn't work.
You need to use expressions in your ORDER BY clause. For test data
ID PFAccNo
-- -------------
1 MH/122020/101
2 MH/122020/2
3 MH/122020/145
4 MH/122020/12
5 MH/122021/1
the query
SELECT PFAccNo, ID
FROM P
ORDER BY
Left(PFAccNo,9),
Val(Mid(PFAccNo,11))
returns
PFAccNo ID
------------- --
MH/122020/2 2
MH/122020/12 4
MH/122020/101 1
MH/122020/145 3
MH/122021/1 5
you have to convert your substring beginning with pos 11 to a number, and the number can be sorted.
How about this ?
SELECT
tmpTbl.yourFieldName
FROM
tmpTbl
ORDER BY
CLng(Mid([tmpTbl].[yourFieldname],InStrRev([tmpTbl].[yourFieldname],"/")+1));
Given the following data in my test_table, column DATETIMESTAMP:
XXX123
YYY000
XXX-1234
my Statement:
SELECT CInt(Mid(datetimestamp,4)) AS Ausdr1
FROM test_data
ORDER BY 1;
sorts my data. please hange 4 to 11 and it will work for you
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'm quite new into SQL and I'd like to make a SELECT statement to retrieve only the first row of a set base on a column value. I'll try to make it clearer with a table example.
Here is my table data :
chip_id | sample_id
-------------------
1 | 45
1 | 55
1 | 5986
2 | 453
2 | 12
3 | 4567
3 | 9
I'd like to have a SELECT statement that fetch the first line with chip_id=1,2,3
Like this :
chip_id | sample_id
-------------------
1 | 45 or 55 or whatever
2 | 12 or 453 ...
3 | 9 or ...
How can I do this?
Thanks
i'd probably:
set a variable =0
order your table by chip_id
read the table in row by row
if table[row]>variable, store the table[row] in a result array,increment variable
loop till done
return your result array
though depending on your DB,query and versions you'll probably get unpredictable/unreliable returns.
You can get one value using row_number():
select chip_id, sample_id
from (select chip_id, sample_id,
row_number() over (partition by chip_id order by rand()) as seqnum
) t
where seqnum = 1
This returns a random value. In SQL, tables are inherently unordered, so there is no concept of "first". You need an auto incrementing id or creation date or some way of defining "first" to get the "first".
If you have such a column, then replace rand() with the column.
Provided I understood your output, if you are using PostGreSQL 9, you can use this:
SELECT chip_id ,
string_agg(sample_id, ' or ')
FROM your_table
GROUP BY chip_id
You need to group your data with a GROUP BY query.
When you group, generally you want the max, the min, or some other values to represent your group. You can do sums, count, all kind of group operations.
For your example, you don't seem to want a specific group operation, so the query could be as simple as this one :
SELECT chip_id, MAX(sample_id)
FROM table
GROUP BY chip_id
This way you are retrieving the maximum sample_id for each of the chip_id.