In what way I can combine Multiple SQL queries?

Question

I am unable to combine two SQL queries into a single one which reflects some great ideas. 

Assume that I have a query A, and query B. Query A returns the total number of working hours. Query B returns the total number of hours where workers could work.

I just want query A over query B. I need to have the information of the percentage of capacity that was worked. 

I can write query A and B independently, but I am unable to figure out the prewritten queries to come up with a new SQL query that uses them together. So tell me how can I write that query.

Answer 1

Try out the following code down below:

SELECT worked/available AS PercentageCapacity

FROM ( SELECT worked FROM A ), 

     ( SELECT available FROM B )

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