I have a table in my database that looks like this.
id count
-----------
1 23
2 20
3 12
4 4
The "count" column will periodically change. How would I add all the values in the count column and display them on the front end? So for example, in this case they would add up to 59.
select sum(count) from table_name
SELECT SUM(`count`) FROM myTable
Related
I want to get exact row count of specified column
Example: Table
Name Id Age
_______________________________
Jon 1 30
Merry 2 40
William 50
David
There are 4 rows in table but i want to count ID column.
I am using below query to achieve it
select count(Id) from table;
But its returning 4 and I know why it is returning 4 but I want output as 2 because there are only two rows in Id column.
How can i achieve it?
Try this:
select count(Id) from table where id>0;
with the help of #blabla_bingo and #Edwin Dijk finally i have achieved it by below query
select count(Id) from table where Id!="";
I'm running a query through my MySQL database (MariaDB 10.3) which goes like this:
SELECT * FROM my_table ORDER BY priority DESC, expiration_date ASC, id ASC
A sample of this table with given ordering would look like this:
id
...
priority
expiration_date
3
...
2
2022-07-01 12:00:00
7
...
2
2022-07-03 12:00:00
6
...
2
2022-07-04 12:00:00
9
...
1
2022-07-02 12:00:00
4
...
1
2022-07-05 12:00:00
11
...
1
2022-07-05 12:00:00
Now I already have the ID of a specific record and I'm trying to retrieve the record which would precede / succeed said record in the query result by the given ordering through SQL as well. Say I have the record ID 6, and I want to have the records with ID 9 and 7 respectively returned.
With an ordering by a single, unique column this would be quite easy to get in a single query, but I'm not sure how to handle multiple non-unique columns. Can someone tell me how to achieve this.
Following Paul Maxwell's hint about LEAD and LAG, I was able to compose a working query like this:
SELECT t.next_id
FROM (
SELECT id,
LEAD(id, 1) OVER (ORDER BY priority DESC, expiration_date ASC, id ASC) AS next_id
FROM my_table
) t
WHERE t.id = ?
Retrieving the previous record works accordingly with LAG.
I have a table with two columns:
id
num
1
2
2
8
1
7
7
3
I want to get as an answer to my query only ids that have more than 1 nums.
For example in my table I would want to get as a result:
id
1
How should I express my query?
Thanks in advance.
You might need something like this:
SELECT id
FROM your_table_name
GROUP BY id
HAVING count(DISTINCT num) > 1;
Google 'Aggregate functions'. Here the aggregate function is count() and it works always coupled with a GROUP BY clause. Pretty fun.
select * from "Test"."EMP"
id
1
2
3
4
5
Select SUM(1) FROM "Test"."EMP";
Select SUM(2) FROM "Test"."EMP";
Select SUM(3) FROM "Test"."EMP";
why the output of these queries is?
5
10
15
And
I don't understand why they write table name like this "Test"."EMP"
your table has 5 records. the statement select 1 from test.emp returns 5 records with values as 1 for all 5 records.
id
1
1
1
1
1
This is because db engine simply returns 1 for each existing record without reading the contents of the cell. and same happens for select <any static value> from test.emp
same happens for 2 and 3
id
2
2
2
2
2
hence there are 5 records returned with the static values and sum of those values will be the product of static number passed in the select statement and total records in the table
additional fact: It is always recommended to perform count(1) than count(*) as it consumes less resource and hence less load on the server
I don't think it's "Test"."EMP" with double quotes.. it's probably `Test`.`EMP` with backticks instead. The definition means its database_name.table_name. This is the recommended format to get the correct table_name from database_name; in this case, you're specifically making the syntax to query from `Test`.`EMP`. Read more about identifier qualifiers.
As for SUM(x), the x get's repeated according to the rows present in the table. So SUM(1) on 5 rows is 1+1+1+1+1, SUM(2) on 5 rows is 2+2+2+2+2, and so on.
I have a data like,
ID Name ItemA ItemB ItemC
OXZ234 Adam 4 4 5
OXZ234 Adam 1 2 3
OXZ345 Tarzen 6 7 8
OXDER2 William 9 8 2
OXDER2 William 0 8 0
I need to find how much of food each person eats. For example by referring first two records I can say, Adam of ID OXZ234 ate ItemA-5, ItemB-6 and ItemC-8. But for small amount of data this kind of manual calculation is affordable. I have a million data records like this. So initially I need to find the records which is having same ID and name but only items count differing.
I have tried the query to find duplicate records by grouping all columns like below,
select ID,Name,ItemA,ItemB,ItemC, COUNT(*)
from DATA_REFRESH
group by ID,Name,ItemA,ItemB,ItemC
having COUNT(*) > 1
But Now I have to identify records having items columns differed.
So the expected output is like,
OXZ234 Adam 2
OXDER2 William 2
OXZ345 Tarzen 1
Any suggestion would be helpful!
You want SUM
select ID,
Name,
sum(ItemA) as ItA,
sum(ItemB) as ItB,
sum(ItemC) as ItC,
count(ID) as Occurrences -- Counts the number of entries per person
from DATA_REFRESH
group by ID,Name
having count(ID) >1 -- restricts this so only those with more than one entry appear
Hi, You can have a simple query without having clause,
select ID,Name,COUNT(*)
from DATA_REFRESH
group by ID,Name order by COUNT(*) desc ;
Simply try like this,
select ID,Name,COUNT(*)
from Sample_Check
group by ID,Name
having COUNT(*) > 1