How to remove NULL from case when and then output Oracle SQL Developer

Oracle SQL Developer noob here. I am trying to create a quarterly sales analysis based on warehouse names and output the Quarterly sales as Q1, Q2 etc. Using Drill down query concepts.

I am unsure if what I am doing is in any way related to a Drill Down concept but this is one of my many attempts. I am hoping for a way to remove the null value outputs to be left with proper data.

It is in the hopes that with the removal of the null data, all the outputs related to specific warehouse names will also all output to 1 line. Leaving me with Warehouse_Name(1), Q1 Data, Q2 Data, etc

I am currently using two tables for this query which are Warehouse: Warehouse_id, warehouse_name and quantity_sold Time_Period: Date_id, Full_date, Days, Month_short and year.

My Code is as follows:

SELECT TO_CHAR(Full_date, 'Q') AS MY_QTR,       Sum(Quantity_sold) AS HOW_MANY_SOLD_PER_QTR  FROM warehouse, Time_Period   GROUP BY TO_CHAR(Full_date, 'Q')  ORDER BY 1;  Select warehouse_Name,  case   when TO_CHAR(Full_date, 'Q') = 1  then Sum(Quantity_sold)   End as Q1_2019,  case   when TO_CHAR(Full_date, 'Q') = 2  then Sum(Quantity_sold)  End as Q2_2019,  case   when TO_CHAR(Full_date, 'Q') = 3  then Sum(Quantity_sold)  End as Q3_2019,  case   when TO_CHAR(Full_date, 'Q') = 4  then Sum(Quantity_sold)  End as Q4_2019  FROM warehouse w1, Time_Period t1  where Q1_2019 IS NOT NULL  GROUP BY warehouse_Name,TO_CHAR(Full_date, 'Q')  ORDER BY 1;  

Which provides me with an output of

Waarehouse_Name|Q1|Q2|Q3|Q4 (Column Names)

Henderson 990(Null)(Null)(Null) (Row Outputs)

Henderson (Null)1001(Null)(Null)

Henderson (Null)1012(Null)(Null)

Henderson (Null)(Null)(Null)1012

https://stackoverflow.com/questions/67249313/how-to-remove-null-from-case-when-and-then-output-oracle-sql-developer April 25, 2021 at 10:50AM