SQL nested query possible?

Question

I have found select statements that basically use different where clauses to count. My question is, how do I combine the results in one statement so that these counts can become columns?

1. select count(*) as c1 from table1 where city = 'nyc'
2. select count(*) as c2 from table1 where city = 'boston'
3. select count(*) as c3 from table1 where city = 'sf'

Answer 1

SELECT
  COUNT(CASE WHEN city = 'nyc' THEN 1 END) AS Nyc,
  COUNT(CASE WHEN city = 'boston' THEN 1 END) AS Boston,
  COUNT(CASE WHEN city = 'sf' THEN 1 END) AS Sf
FROM table

Answer 2

You can give GROUP BY a chance,

SELECT city, gender, count(*)
WHERE gender = "male"
GROUP BY city, gender;