Edited to provide sample data
I am trying to create a calculated column that sums 2 other columns, which should be easy. However, some values in both of the columns are null, so I want to use a case expression to replace null values in both columns with 0s and then add up the resulting values. The other complicating factor is that the second column contains text values with commas that need to be converted to numerical before I can add them. What I am currently trying to do is:
SELECT (case when pm."PS" is null then 0 else pm."PS" end) + (case when pm."PS-PREV1" is null then 0 else replace(pm."PS-PREV1", ',', '')::numeric end) AS "Sales"
FROM pm
Sample data:
PS
PS-PREV1
20000
null
30000
20,000
null
null
null
30,000
Desired output:
output
20000
50000
0
30000
This is just returning the value of the 1st column without adding in the second column. Where am I going wrong? Am I overthinking this?
your code should work , however you can write it a little bit more clean:
SELECT COALESCE(pm."PS",0)
+ COALESCE(replace(pm."PS-PREV1", ',', '')::numeric,0) AS "Sales"
FROM pm
Related
I have two issues:
I am trying to create a pivot table using the crosstabs tablefunc but all of the queries I've tried are returning NULL for all values.
I have two grouping variables (airport code and date) that are in one row of data that need to be separate columns in the pivot table, but I can only seem to get one to work.
I have gotten the pivot table to partially work by ignoring the date value for the moment. When I leave 'yyyymm' out of my query, the setup of my output table is okay, but the values don't calculate properly.
The data: I have rows with various airport codes, aircraft user and engine codes, flight identifiers, and year/month values. Each row counts for one flight. A simplified example looks like this:
ident
primary_fa
user_engn
yyyymm
20191122-AFR-23
MKE
O_O
201911
20191210-ASH-61
N90
T_R
201912
20200120-EDV-2
MKE
C_J
202001
20200811-FLC-148
A90
O_O
202008
I need my output table to count the number of arrivals for each user engine combo grouped by airport code and yyyymm. So the rows would be each airport code (primary_fa), yyyymm and columns would be user_engn codes (O_O, T_R, C_J, etc.) with counts for the number of flights per user_engn.
My goal output would look something like this:
primary_fa
yyyymm
C_J
T_R
O_O
MKE
201911
1
0
1
N90
201912
0
1
0
A90
202008
0
0
1
But I am getting this (because I have to ignore the date portion to even get this far):
primary_fa
C_J
T_R
O_O
MKE
NULL
NULL
NULL
N90
NULL
NULL
NULL
A90
NULL
NULL
NULL
I've tried a lot of different versions of the crosstabs query and the closest I have gotten to correct is this:
SELECT *
FROM crosstab(
'SELECT primary_fa as locid,
yyyymm,
count(*)
FROM fy20_keeps_emdf
GROUP BY primary_fa, yyyymm
ORDER BY 1,2',
'VALUES (''C_J''),(''O_O''),(''T_R'')')
AS (primary_fa varchar,
C_J bigint,
O_O bigint,
T_R bigint);
Am I missing something obvious or do I need to do more data manipulation to get this to work?
Suppose that I have a lot of NULL values (missing values) in a column named 'score'. I want to replace them by a specific average not from all the values of the column 'score' but by groups that I built with a crosscategory from two concatenated categories:
This kind of query works for getting averages by groups:
SELECT
category1 || ' > ' || category2 AS crosscategory,
ROUND(CAST(AVG(score) AS FLOAT), 2) AS score_avg
FROM DatabaseName.TableName
GROUP BY crosscategory
ORDER BY score_avg;
This one works to replace NULL values by a constant:
SELECT
NVL(score, 0) AS score_without_missing_values
FROM DatabaseName.TableName
The problem that I cannot solve now is how to articulate the replacement of NULL values with a constant here the averages computed with the functions AVG and GROUP BY.
Thank you very much for your help!
Seems you want a Group Average:
SELECT
t.*,
coalesce(score, AVG(score) OVER (PARTITION BY category1, category2)) AS score_avg
FROM DatabaseName.TableName AS t
I removed the ROUND/CAST, because AVG returns FLOAT by default and ROUND in probably not needed (if you need it, you might better cast to a DECIMAL).
original query looks like this :
UPDATE reponse_question_finale t1, reponse_question_finale t2 SET
t1.nb_question_repondu = (9-(ISNULL(t1.valeur_question_4)+ISNULL(t1.valeur_question_6)+ISNULL(t1.valeur_question_7)+ISNULL(t1.valeur_question_9))) WHERE t1.APPLICATION = t2.APPLICATION;
I know you cannot update 2 tables in a single query so i tried this :
UPDATE reponse_question_finale t1
SET nb_question_repondu = (9-(COALESCE(t1.valeur_question_4,'')::int+COALESCE(t1.valeur_question_6,'')::int+COALESCE(t1.valeur_question_7)::int+COALESCE(t1.valeur_question_9,'')::int))
WHERE t1.APPLICATION = t1.APPLICATION;
But this query gaves me an error : invalid input syntax for integer: ""
I saw that the Postgres equivalent to MySQL is COALESCE() so i think i'm on the good way here.
I also know you cannot add varchar to varchar so i tried to cast it to integer to do that. I'm not sure if i casted it correctly with parenthesis at the good place and regarding to error maybe i cannot cast to int with coalesce.
Last thing, i can certainly do a co-related sub-select to update my two tables but i'm a little lost at this point.
The output must be an integer matching the number of questions answered to a backup survey.
Any thoughts?
Thanks.
coalesce() returns the first non-null value from the list supplied. So, if the column value is null the expression COALESCE(t1.valeur_question_4,'') returns an empty string and that's why you get the error.
But it seems you want something completely different: you want check if the column is null (or empty) and then subtract a value if it is to count the number of non-null columns.
To return 1 if a value is not null or 0 if it isn't you can use:
(nullif(valeur_question_4, '') is null)::int
nullif returns null if the first value equals the second. The IS NULL condition returns a boolean (something that MySQL doesn't have) and that can be cast to an integer (where false will be cast to 0 and true to 1)
So the whole expression should be:
nb_question_repondu = 9 - (
(nullif(t1.valeur_question_4,'') is null)::int
+ (nullif(t1.valeur_question_6,'') is null)::int
+ (nullif(t1.valeur_question_7,'') is null)::int
+ (nullif(t1.valeur_question_9,'') is null)::int
)
Another option is to unpivot the columns and do a select on them in a sub-select:
update reponse_question_finale
set nb_question_repondu = (select count(*)
from (
values
(valeur_question_4),
(valeur_question_6),
(valeur_question_7),
(valeur_question_9)
) as t(q)
where nullif(trim(q),'') is not null);
Adding more columns to be considered is quite easy then, as you just need to add a single line to the values() clause
I'm using the following query to sum the entire column. In the TOREMOVEALLPRIV column, I have both integer and null values.
I want to sum both null and integer values and print the total sum value.
Here is my query which print the sum values as null:
select
sum(URT.PRODSYS) as URT_SUM_PRODSYS,
sum(URT.Users) as URT_SUM_USERS,
sum(URT.total_orphaned) as URT_SUM_TOTAL_ORPHANED,
sum(URT.Bp_errors) as URT_SUM_BP_ERRORS,
sum(URT.Ma_errors) as URT_SUM_MA_ERRORS,
sum(URT.Pp_errors) as URT_SUM_PP_ERRORS,
sum(URT.REQUIREURTCBN) as URT_SUM_CBNREQ,
sum(URT.REQUIREURTQEV) as URT_SUM_QEVREQ,
sum(URT.REQUIREURTPRIV) as URT_SUM_PRIVREQ,
sum(URT.cbnperf) as URT_SUM_CBNPERF,
sum(URT.qevperf) as URT_SUM_QEVPERF,
sum(URT.privperf) as URT_SUM_PRIVPERF,
sum(URT.TO_REMOVEALLPRIV) as TO_REMOVEALLPRIV_SUM
from
URTCUSTSTATUS URT
inner join CUSTOMER C on URT.customer_id=C.customer_id;
Output image:
Expected Output:
Instead of null, I need to print sum of rows whichever have integers.
The SUM function automatically handles that for you. You said the column had a mix of NULL and numbers; the SUM automatically ignores the NULL values and correctly returns the sum of the numbers. You can read it on IBM Knowledge Center:
The function is applied to the set of values derived from the argument values by the elimination of null values.
Note: All aggregate functions ignore NULL values except the COUNT function. Example: if you have two records with values 5 and NULL, the SUM and AVG functions will both return 5, but the COUNT function will return 2.
However, it seems that you misunderstood why you're getting NULL as a result. It's not because the column contains null values, it's because there are no records selected. That's the only case when the SUM function returns NULL. If you want to return zero in this case, you can use the COALESCE or IFNULL function. Both are the same for this scenario:
COALESCE(sum(URT.TO_REMOVEALLPRIV), 0) as TO_REMOVEALLPRIV_SUM
or
IFNULL(sum(URT.TO_REMOVEALLPRIV), 0) as TO_REMOVEALLPRIV_SUM
I'm guessing that you want to do the same to all other columns in your query, so I'm not sure why you only complained about the TO_REMOVEALLPRIV column.
What you're looking for is the COALESCE function:
select
sum(URT.PRODSYS) as URT_SUM_PRODSYS,
sum(URT.Users) as URT_SUM_USERS,
sum(URT.total_orphaned) as URT_SUM_TOTAL_ORPHANED,
sum(URT.Bp_errors) as URT_SUM_BP_ERRORS,
sum(URT.Ma_errors) as URT_SUM_MA_ERRORS,
sum(URT.Pp_errors) as URT_SUM_PP_ERRORS,
sum(URT.REQUIREURTCBN) as URT_SUM_CBNREQ,
sum(URT.REQUIREURTQEV) as URT_SUM_QEVREQ,
sum(URT.REQUIREURTPRIV) as URT_SUM_PRIVREQ,
sum(URT.cbnperf) as URT_SUM_CBNPERF,
sum(URT.qevperf) as URT_SUM_QEVPERF,
sum(URT.privperf) as URT_SUM_PRIVPERF,
sum(COALESCE(URT.TO_REMOVEALLPRIV,0)) as TO_REMOVEALLPRIV_SUM
from
URTCUSTSTATUS URT
inner join CUSTOMER C on URT.customer_id=C.customer_id;
I am relatively new to Tableau and I am wondering if there is a way to calculate null values in a column.
I have a column called Email of type string and want to know how many people have not entered their email i.e. Null.
I tried to create a calculated field with
count(ISNULL([Email]))
But this gives me the total count and not the count of null.
Thanks.
You cannot count NULL since COUNT ignores NULLs.
You can do this, though:
SUM(IF ISNULL([Email]) THEN 1 ELSE 0 END)
Per your additional comment, if you wanted to count where two fields are both NULL then:
SUM(IF ISNULL([Email]) AND ISNULL([Phone]) THEN 1 ELSE 0 END)
You can continue this for any number of fields, as needed.
You can use a filter for that field. Set it to only show you Null values, and set the measure to Count instead of the default Sum.
You can create another column where all null values are set to 1 and anything else to 0, >then count that. It should be something like
>COUNT(IF "null" THEN 1 ELSE 0)
A working syntax for that would had been:
SUM(IF ([Your field] = null) THEN 1
ELSE 0
END)
You can create another column where all null values are set to 1 and anything else to 0, then count that. It should be something like
COUNT(IF "null" THEN 1 ELSE 0)