如何將總計添加為sql的最后一行？

Question

我正在嘗試顯示“總計”行，該行將做“計數”列的總和。 以下代碼將包含兩列，即“環境”和“計數”。

select 
case 
when env is null THEN 'Unknown' 
else env
end,
count(*) as Count
from env_table
group by env
order by env
/

我想要的輸出：

Windows 200

Linux 120

總計320

正如您在上面看到的，我想做的是在末尾添加一行稱為“總計”的行，該行實際上將執行SUM（count（*））。 正確的語法是什么？ 謝謝！

Answer 1

使用WITH ROLLUP修飾符對GROUP BY ：

SELECT   IFNULL(env, 'Unknown'),
         COUNT(*) AS Count
FROM     env_table
GROUP BY env WITH ROLLUP
ORDER BY env

Answer 2

也許是這樣的嗎？

SELECT   IFNULL(env, 'Unknown'),
         COUNT(*) AS Count
FROM env_table
GROUP BY env
ORDER BY env
UNION ALL
SELECT   null,
         Count(*)
FROM env_table

Answer 3

SELECT env, count 
  FROM (SELECT CASE WHEN env is null THEN 'Unknown' ELSE env END env,
               count(*) count
          FROM env_table
         GROUP BY env
      ORDER BY env)
UNION ALL
SELECT 'Total' env,
       count(*) count
  FROM env_table       

Answer 4

SELECT   COALESCE(env, 'Total') AS Description,
         COUNT(*) AS Count
FROM     env_table
GROUP BY env WITH ROLLUP
ORDER BY env