I am not able to understand the SQL query output :
SQL> select distinct(STATUS) from TMP_ORDER_ACTION_PSTN_CP_11035;
InDelivery_SOMBe
In Delivery
Complete
Amended
Cancelled
Failed InComplete
1 SQL> select count(*) from TMP_ORDER_ACTION_PSTN_CP_11035 where
STATUS='Complete';
1484
2 SQL> select count(*) from TMP_ORDER_ACTION_PSTN_CP_11035 where STATUS
!= 'Complete';
3167
3 SQL> select count(*) from TMP_ORDER_ACTION_PSTN_CP_11035;
5091
The sum of count for the 1 and 2 queries should be same as the total count(3 query).Why is the sum differing from the whole count?
It seems like a dump question but i dont know why is this happening.
Please note that My question is not related to null check at all.It is the that
sum(1+2)=3.1484+3167 !=5091.Why is the result different?
My guess is NULL values, which match none of your WHERE clauses, including the last one. Try
select count(*) from TMP_ORDER_ACTION_PSTN_CP_11035 where STATUS is null;
where status = null is never true, nor is where null = null. You have to use is null.
The sum of count for the 1 and 2 queries should be same as the total count(3 query).Why is the sum differing from the whole count?
No, because the records with NULL are not matching query 1 or query 2, but they are counted in query 3.
1 + 2 + IS NULL should equal 3.
WHERE STATUS = NULL won't work. Nothing equals NULL.
Try IS instead of =...
select count(*) from TMP_ORDER_ACTION_PSTN_CP_11035 where STATUS IS null
Try this:
Assuming p_key is a primary key for the table,
select count(p_key) from TMP_ORDER_ACTION_PSTN_CP_11035 where STATUS='Complete';
select count(p_key) from TMP_ORDER_ACTION_PSTN_CP_11035 where STATUS <> 'Complete';
select count(p_key) from TMP_ORDER_ACTION_PSTN_CP_11035 ;
Related
i am trying to do a count on null values however , it is not able to count null values.
example of table :
Country Id Id_typ Info
Us 123 NULL Testing
Us 124 NULL Testing
Us 125 Bob testing
this is my script to count null values
select count(id_typ) from combined_a where id_typ= 'NULL' limit 1
i have tried
select count(id_typ) from table_a where id_typ is null limit 1
however when i have change the condition to search id_typ = bob, it was able to do a count . i am unsure on what did i do wrong , any advice?
You need is null and count(*):
select count(*)
from table_a
where id_typ is null;
limit 1 is redundant. A SQL query with an aggregation function and no group by always returns one row.
select 1 from MY_TABLE where ID=42 fetch first 1 rows only;
select 1 from MY_TABLE where ID=42 and rownum=1;
select case when exists (select 1 from MY_TABLE where ID=42) then 1 else 0 end from dual;
select count(1) from MY_TABLE where ID=42;
Here is 4 methods to check whether the table contains any rows. The last one is quite slow, but first 3 has approximatively the same time. What is the best practice (academically correct)?
Any other methods?
Unless throwing an exception is acceptable, in which case you will need to capture it, you will want to use a count with rownum = 1
select count(*) from my_table where id = 42 and rownum = 1;
In this case, the return value of 0 means there are no rows, 1 means there are 1 or more rows.
While this gives the same results as your select with case statement, it is much less complicated and easier to understand.
I have this
RECORD ITEMS ITEMSTOTAL
------------------------------------ ---------- ----------
ababababaa 0 1
ababababab 0 0
ababababac 0 1
ababababad 1 1
ababababae 0 2
but I need this output when ITEMS=ITEMSTOTAL
RECORD
------------------------------------
ababababab
ababababad
Currently I'm using this query for the first result, but I don't know how to get the second output, Maybe this sounds obvious but I can't find the answer :(
SELECT RECORD,
(SELECT COUNT(*) FROM TABLE1 WHERE SOMETHING=X) AS ITEMS,
(SELECT COUNT(*) FROM TABLE2 WHERE SOMETHING2=Y) AS ITEMSTOTAL
FROM RECORDS_TABLE
WHERE DELETED=0
--and ITEMS.count = ITEMSTOTAL.count <-- tried something like this but it doesn't work.
One option would be to use a subquery and apply the where criteria to the outer query.
select *
from (
your query here
) t
where items = itemstotal
I assume that isn't your actual query btw. where comes after from. Also, those count statements would return the same values.
I have the following SQL Code which is not giving me my desired results.
SELECT
POLICIES.CLIENTS_ID,
POLICIES.CLIENTCODE,
COUNT(POLICIES.POLICIES_ID) as [Total Policies],
(
SELECT
COUNT(POLICIES.POLICIES_ID)
FROM
POLICIES
WHERE
POLICIES.COVCODE = 'AUT'
) as [Auto Policies]
FROM
POLICIES
LEFT JOIN CLIENTS
ON CLIENTS.CLIENTS_ID = POLICIES.CLIENTS_ID
WHERE
POLICIES.CNR IS NULL
GROUP BY
POLICIES.CLIENTS_ID,
POLICIES.CLIENTCODE
ORDER BY
POLICIES.CLIENTS_ID
I get a result like this:
ID CODE Total Auto
3 ABCDE1 1 999999
4 ABCDE2 1 999999
5 ABCDE3 2 999999
6 ABCDE4 2 999999
I would like for the last column to COUNT the total auto policies that exists for that clientid rather than all of the auto policies that exist. I believe I need a nested select statement that somehow groups all like results on the clientid, but it ends up returning more than 1 row and throws the error.
If I add:
GROUP BY
POLICIES.CLIENTS_ID
I get:
Subquery returned more than 1 value. This is not permitted when the....
Any help would be appreciated greatly!
Thank you
You can use a CASE statement to do this. Instead of your subquery in the SELECT clause use:
SUM(CASE WHEN POLICIES.COVCODE = 'AUT' THEN 1 ELSE 0 END) as [AUTO POLICIES]
As Martin Smith pointed out. If client_id has multiple client_codes then this will give you the count of records for each combination of client_id/client_code. If client_id is 1:1 with client_code then this will give you a count of records for each distinct client_id, which I suspect is the case from your example and question.
Unrelated: You have a LEFT JOIN to your Clients table, but you don't use your Clients table anywhere int he query. Consider removing it if you don't need to select or filter by any its fields, since it's just unused overhead.
What if you modify the inner query for getting count to something like
SUM(CASE WHEN POLICIES.COVCODE = 'AUT' THEN 1 ELSE 0 END) as [Auto Policies]
I have a table
num
----
NULL
NULL
NULL
NULL
55
NULL
NULL
NULL
99
when I wrote
select COUNT(*)
from tbl
where num is null
the output was 7
but when I wrote
select COUNT(num)
from tbl
where num is null
the output was 0
what's the difference between these two queries ??
Difference is in the field you select.
When counting COUNT(*) NULL values are taken into account (count all rows returned).
When counting COUNT(num) NULL values are NOT taken into account (count all non-null fields).
That is a standard behavior in SQL, whatever the DBMS used
Source. look at COUNT(DISTINCT expr,[expr...])
count(*) returns number of rows, count(num) returns number of rows where num is not null. Change your last query to select count(*) from test where num is null to get the result you expect.
In second case first count values are eliminated and then where clause comes in picture. While in first case when you are using * row with null is not eliminated.
If you are counting on a coll which contains null and you want rows with null to be included in count than use
Count(ISNULL(col,0))
Count(*) counts the number of rows, COUNT(num) counts the number of not-null values in column num.
Considering the output given above, the result of the query count(num) should be 2.