題目描述
從titles表獲取按照title進行分組，每組個數大於等於2，給出title以及對應的數目t。
CREATE TABLE IF NOT EXISTS "titles" (
`emp_no` int(11) NOT NULL,
`title` varchar(50) NOT NULL,
`from_date` date NOT NULL,
`to_date` date DEFAULT NULL);
CREATE TABLE IF NOT EXISTS "titles" (
`emp_no` int(11) NOT NULL,
`title` varchar(50) NOT NULL,
`from_date` date NOT NULL,
`to_date` date DEFAULT NULL);
輸入描述:
無
輸出描述:
| title | t |
|---|---|
| Assistant Engineer | 2 |
| Engineer | 4 |
| 省略 | 省略 |
| Staff | 3 |
SQL:
select title,count(title) as t from titles group by title having t>=2
用count和group by 統計同一條數據