![计算以特定条件开头的唯一值](https://linux22.com/image/1519713/%E8%AE%A1%E7%AE%97%E4%BB%A5%E7%89%B9%E5%AE%9A%E6%9D%A1%E4%BB%B6%E5%BC%80%E5%A4%B4%E7%9A%84%E5%94%AF%E4%B8%80%E5%80%BC.png)
从数据列中查看有多少个以 CC 开头的唯一值(=3)
AB0010
CC0009
AB0010
EF0011
CC1001
AB0090
CC1001
(empty field)
CC1001
CC2001
从...开始:
AB = 2
CC = 3
EF = 1
从数据列中查看有多少个以 CC 开头的唯一值(=3)
AB0010
CC0009
AB0010
EF0011
CC1001
AB0090
CC1001
(empty field)
CC1001
CC2001
从...开始:
AB = 2
CC = 3
EF = 1