I want count the number of times a single data occured in a column, how can I achieve that using mysqli. For instance I want to know the number of times Victor appeared in the column of name.
If you're using SQL server:
SELECT name, count(1)
from Tablename
where name like 'Victor'
group by name
This query will give you results like - eg Victor appeared 22 times:
Victor 22
Is this what you're looking for?
Please provide more information so its easier to assist.
Try window functions
SELECT ROW_NUMBER() OVER(PARTITION BY Name ORDER BY Name DESC)
AS Total, Name from table
this one will give you count of records with name='Victor'
select count(name) as cnt from t where name='Victor'
this one will give you all names with counts
select name, count(1) as cnt
from t
group by name
order by name
Related
I have a relation CandyC(id, email, age, name, candy_id)
I want to count the CandyC.ids associated with a CandyC.candy_id once.
Attempt:
SELECT email, age, name
FROM CandyC
GROUP BY id
HAVING COUNT(DISTINCT candy_id) = 1;
It gives me an error:
not a group by expression
The group by clause need to have all the non aggregated columns selected directly. Also, it's usually a good idea to use having after the group by as it's the standard way of writing this (even though Oracle supports it the other way too).
Does this do what you want:
select email, age, name
from candyc
group by id, email, age, name
having count(distinct candy_id) = 1
If not, you should provide sample data and expected results in your question to clarify.
I think you want something more like this:
SELECT candy_id, COUNT(*)
FROM CandyC
GROUP BY candy_id;
I don't know what the email/age/name columns have to do with the question:
I want to count the CandyC.ids associated with a CandyC.candy_id once.
I need the second column of the table retrieved from a query to have a count of the number of rows, so row one would have a 1, row 2 would have a 2 and so on. I am not very proficient with sql so I am sorry if this is a simple task.
A basic example of what I am doing would be is:
SELECT [Name], [I_NEED_ROW_COUNT_HERE],[Age],[Gender]
FROM [customer]
The row count must be the second column and will act as an ID for each row. It must be the second row as the text file it is generating will be sent to the state and they require a specific format.
Thanks for any help.
With your edit, I see that you want a row ID (normally called row number rather than "count") which is best gathered from a unique ID in the database (person_id or some other unique field). If that isn't possible, you can make one for this report with ROW_NUMBER() OVER (ORDER BY EMPLOYEE_ID DESC) AS ID, in your select statement.
select Name, ROW_NUMBER() OVER (ORDER BY Name DESC) AS ID,
Age, Gender
from customer
This function adds a field to the output called ID (see my tips at the bottom to describe aliases). Since this isn't in the database, it needs a method to determine how it will increment. After the over keyword it orders by Name in descending order.
Information on Counting follows (won't be unique by row):
If each customer has multiple entries but the selected fields are the same for that user and you are counting that user's records (summed in one result record for the user) then you would write:
select Name, count(*), Age, Gender
from customer
group by name, age, gender
This will count (see MSDN) all the user's records as grouped by the name, age and gender (if they match, it's a single record).
However, if you are counting all records so that your whole report has the grand total on every line, then you want:
select Name, (select count(*) from customer) as "count", Age, Gender
from customer
TIP: If you're using something like SSMS to write a query, dragging in columns will put brackets around the columns. This is only necessary if you have spaces in column names, but a DBA will tend to avoid that like the plague. Also, if you need a column header to be something specific, you can use the as keyword like in my first example.
W3Schools has a good tutorial on count()
The COUNT(column_name) function returns
the number of values (NULL values will not be counted) of the
specified column:
SELECT COUNT(column_name) FROM table_name;
The COUNT(*) function returns the number of records in a table:
SELECT COUNT(*) FROM table_name;
The COUNT(DISTINCT column_name) function returns the number of
distinct values of the specified column:
SELECT COUNT(DISTINCT column_name) FROM table_name;
COUNT(DISTINCT) works with ORACLE and Microsoft SQL Server, but
not with Microsoft Access.
It's odd to repeat the same number in every row but it sounds like this is what you're asking for. And note that this might not work in your flavor of SQL. MS Access?
SELECT [Name], (select count(*) from [customer]), [Age], [Gender]
FROM [customer]
Using SQL Server, I have a table that looks like this:
What I need to do is write a query to identify scenarios where the Name and Permissions field are equal so that I can give give them a unique Set ID.
For instance, rows 2 and 4 would be a set I can give a SetID as well as rows 6 and 7 are a set that I can give another SetID. But rows 2 and 3 are NOT a set.
So far I have tried using DENSE_RANK () Over(Order by Name) which helps to add an id based on like Names but doesn't take into account matching permissions. And have tried joining the table on itself but with millions of rows of data I end up with unwanted duplicates.
The logic I am following is this:
If (Name and Permissions) of one row = (Name and Permissions) of another row give them a SetID to share.
Please help I have been banging my head against the wall with this one. Ideally a SQL query would accomplish this but am open to anything.
Thank you!
You could do it for example like this:
select
Name,
Permission,
row_number() over (order by Name, Permission) as RN
from (
select distinct
Name,
Permission
from
permissions
) TMP
order by Name, Permission
The inner select gets the distinct combinations, and the outer one assigns the numbers.
SQL Fiddle: http://sqlfiddle.com/#!6/c8319/3
This will probably do something similar to what you want.
SELECT
name,
permissions,
accountname,
ROW_NUMBER() OVER (PARTITION BY name,permissions ORDER By name,permissions) as SetID
FROM table;
I have a table (named trxItemdata) which contains over 40 columns and 60million rows. One of these columns, named ActivityDateDate shows the date/year associated with each CustomerID (another column in the table).
What I would like to do is find the number of rows for allocated to each year (2010,2011,etc), such that I get a table that looks like this in the results output:
Year Number of Rows
2011 100
2012 10000
2013 10000000
I was looking into the following code but am not too familiar with group by clauses:
select count(*) from trxItemdata
group by year(ActivityDateDate)
However when I run this I get the following table but am not sure what it means:
No Column Name
33060000
27546960
2941697
Any help you could provide would be appreciated! Thanks!
try
select year(activityDateDate) as [Year], count(1) as [Number Of Rows]
from trxItemdata
group by year(ActivityDateDate)
order by year(ActivityDateDate)
Does your date column really have "DateDate"? :P
Your query is not naming the column. Try this:
SELECT YEAR(ActivityDateDate) AS [Year],
COUNT(*) AS NumberOfRows
FROM trxItemdata
GROUP BY YEAR(ActivityDateDate)
I have a table with columns
ID, DateStamp
and the ID need not be unique.
How do I write a query that will give me a list of IDs with the minimum DateStamp and the maximum DateStamp?
So, for example, for a given ID, the output may look like:
938423, 1/1/2000, 12/13/2003
[I am running SQL Server 2000.]
The following should do it:
SELECT ID, MIN(DateStamp), MAX(DateStamp)
FROM TableName
GROUP BY ID
EDIT Added from clause for clarity, be sure to change TableName to the actual table name