I need to count all the distinct records in a table name with a single query and also without using any sub-query.
My code is
select count ( distinct *) from table_name
It gives an error:
Incorrect syntax near '*'.
I am using Microsoft SQL Server
Try this -
SELECT COUNT(*)
FROM
(SELECT DISTINCT * FROM [table_name]) A
I'm afraid that if you don't want to use a subquery, the only way to achieve that is replacing * with a concatenation of the columns in your table
select count(distinct concat(column1, column2, ..., columnN))
from table_name
To avoid undesired behaviours (like the concatenation of 1 and 31 becoming equal to the concatenation of 13 and 1) you could add a reasonable separator
select count(distinct concat(column1, '$%&£', column2, '$%&£', ..., '$%&£', columnN)
from table_name
You can use CTE.
;WITH CTE AS
(
SELECT DISTINCT * FROM TableName
)
SELECT COUNT(*)
FROM CTE
Hope this query gives you what you required.
As others mentioned, you cannot use DISTINCT with *. Also it is good practice to use a column name instead of the *, like a unique key / primary key of the table.
SELECT COUNT( DISTINCT id )
FROM table
select distinct Name , count(Name) from TableName
group by Name
having count(Name)=1
select ##rowcount
I had the same issue involving a query that had multiple joins to tables and I could not simply do count(distinct ) or count(distinct alias.).
My solution was to create a string made up of the key columns I cared about and count them.
SELECT Count(DISTINCT person.first || '~' || person.last)
from person;
If you want to use DISTINCT keyword, you need to specify column name on which bases you want to get distinct records.
Example:
SELECT count(DISTINCT Column-Name) FROM table_name
Related
fairly new to PostgreSQL and trying out a few count queries. I'm looking to count and count distinct all values in a table. Pretty straightforward -
CountD Count
351 400
With a query like this:
SELECT COUNT(*)
COUNT(id) AS count_id,
COUNT DISTINCT(id) AS count_d_id
FROM table
I see that I can create a single column this way:
SELECT COUNT(*) FROM (SELECT DISTINCT id FROM table) AS count_d_id
But the title (count_d_id) doesn't come through properly and unsure how can I add an additional column. Guidance appreciated
This is the correct syntax:
SELECT COUNT(id) AS count_id,
COUNT(DISTINCT id) AS count_d_id
FROM table
Your original query aliases the subquery rather than the column. You seem to want:
SELECT COUNT(*) AS count_d_id FROM (SELECT DISTINCT id FROM table) t
-- column alias --^ -- subquery alias --^
I don't understand why I can't use this in my code :
SELECT MAX(SMTHNG), COUNT(MAX(SMTHNG))
FROM SomeTable;
Searched for an answer but didn't find it in documentation about these aggregate functions.
Also I get an SQL-compiler error "Invalid column name "SMTHNG"".
You want to know what the maximum SMTHNG in the table is with:
SELECT MAX(SMTHNG) FROM SomeTable;
This is an aggregation without GROUP BY and hence results in one single row containing the maximum SMTHNG.
Now you also want to know how often this SMTHNG occurs and you add COUNT(MAX(SMTHNG)). This, however, does not work, because you can not aggregate an aggregate directly.
This doesn't work either:
SELECT ANY_VALUE(max_smthng), COUNT(*)
FROM (SELECT MAX(smthng) AS max_smthng FROM sometable) t;
because the sub query only contains one row, so it's too late to count.
So, either use a sub query and select from the table again:
SELECT ANY_VALUE(smthng), COUNT(*)
FROM sometable
WHERE smthng = (SELECT MAX(smthng) FROM sometable);
Or count per SMTHNG before looking for the maximum. Here is how to get the counts:
SELECT smthng, COUNT(*)
FROM sometable
GROUP BY smthng;
And the easiest way to get the maximum from this result is:
SELECT TOP(1) smthng, COUNT(*)
FROM sometable
GROUP BY smthng
ORDER BY COUNT(*) DESC;
First of all, please read my comment.
Depending on what you're trying to achieve, the statement have to be changed.
If you want to count the highest values in SMTHNG field, you may try this:
SELECT T1.SMTHNG, COUNT(T1.SMTHNG)
FROM SomeTable T1 INNER JOIN
(
SELECT MAX(SMTHNG) AS A
FROM SomeTable
) T2 ON T1.SMTHNG = T2.A
GROUP BY T1.SMTHNG;
use cte like below or subquery
with cte as
(
select count(*) as cnt ,col from table_name
group by col
) select max(cnt) from cte
you can not use double aggregate function at a time on same column
I am getting error while executing the following query.
SELECT COUNT(distinct *) AS "total unique records" FROM table
Please help me to resolve this issue
Because * is not allowed there. If you want to do this, use a subquery:
select count(*)
from (select distinct t.*
from t
) t;
You probably want :
select count(*)
from (select distinct t.*
from table t
) t;
Use this code too count row
SELECT COUNT(*) AS TotalRecords FROM table
AND use that too count row and return order columns
SELECT COUNT(*) OVER() AS TotalRecords,* FROM table
Can i select all rows that have same column value (for example SSN field) but display them all separably. ?
I've searched for this answer but they all have "count(*) and group by" section that demands the rows to be exactly same.
Try This:
SELECT A, B FROM MyTable
WHERE A IN
(
SELECT A FROM MyTable GROUP BY A HAVING COUNT(*)>1
)
I have done with SQL server. But hope this is what you need
Here is another approach, which only references the table once, using an analytic function instead of a subquery to get the duplicate counts It might be faster; it also might not, depending on the particular data.
SELECT * FROM (
SELECT col1, col2, col3, ssn, COUNT(*) OVER (PARTITION BY ssn) ssn_dup_count
)
WHERE ssn_dup_count > 1
ORDER BY ssn_dup_count DESC
SELECT
*
FROM
MyTable
WHERE
EXISTS
(
SELECT
NULL
FROM
MyTable MT
WHERE
MyTable.SameColumnName = MT.SameColumnName
AND MyTable.DifferentColumnName <> MT.DifferentColumnName)
This will fetch the required data and show them in order so that we can see the grouped data together.
SELECT * FROM TABLENAME
WHERE SSN IN
(
SELECT SSN FROM TABLENAMEGROUP BY SSN HAVING COUNT(SSN)>1
)
ORDER BY SSN
Here SSN is the column names fro which similar value check is done.
If i perform a standard query in SQLite:
SELECT * FROM my_table
I get all records in my table as expected. If i perform following query:
SELECT *, 1 FROM my_table
I get all records as expected with rightmost column holding '1' in all records. But if i perform the query:
SELECT *, COUNT(*) FROM my_table
I get only ONE row (with rightmost column is a correct count).
Why is such results? I'm not very good in SQL, maybe such behavior is expected? It seems very strange and unlogical to me :(.
SELECT *, COUNT(*) FROM my_table is not what you want, and it's not really valid SQL, you have to group by all the columns that's not an aggregate.
You'd want something like
SELECT somecolumn,someothercolumn, COUNT(*)
FROM my_table
GROUP BY somecolumn,someothercolumn
If you want to count the number of records in your table, simply run:
SELECT COUNT(*) FROM your_table;
count(*) is an aggregate function. Aggregate functions need to be grouped for a meaningful results. You can read: count columns group by
If what you want is the total number of records in the table appended to each row you can do something like
SELECT *
FROM my_table
CROSS JOIN (SELECT COUNT(*) AS COUNT_OF_RECS_IN_MY_TABLE
FROM MY_TABLE)