Question

I have a table as shown below

Col1    Col2    Col3
*         $       *
$         *       *
#         *       $
%         *       *
*         *       $
*         @       $

I want a sql query to count the number of stars(*) present in the table.

one option is to write the query in the following manner.

select ((select count(*) from star_table where col1='*') + 
(select count(*) from star_table where col2='*') +
(select count(*) from star_table where col3='*')) as count from dual.

I want to know if there is an alternative way of writing the query to get the same result.

Answer 1

select sum(
             case when col1='*' then 1 else 0 end +
             case when col2='*' then 1 else 0 end +
             case when col3='*' then 1 else 0 end            
       ) 
from star_table;  

UPDATE: If your columns contains on character length strings, you can:

select sum(3 - length(replace(col1||col2||col3,'*')))
from star_table; 

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