使い方
SELECT
COUNT(CASE WHEN 残業時間 BETWEEN 0 AND 10 THEN 1 ELSE NULL END) AS [0_10時間],
COUNT(CASE WHEN 残業時間 BETWEEN 11 AND 20 THEN 1 ELSE NULL END) AS [11_20時間]
・・・
FROM 対象テーブル
参考
https://zukucode.com/2020/08/sql-count-null.html
SELECT
COUNT(CASE WHEN 残業時間 BETWEEN 0 AND 10 THEN 1 ELSE NULL END) AS [0_10時間],
COUNT(CASE WHEN 残業時間 BETWEEN 11 AND 20 THEN 1 ELSE NULL END) AS [11_20時間]
・・・
FROM 対象テーブル