SELECT YEAR，COUNT(*)FROM table name GROUP BY 1。
Count the number of readers in each department, and display the name and number of departments.
Select "RDE, quantity (b.bno)" as the quantity.
Add book borrowing b from the left of reader R.
On RNO = RNO
RDE group
Extended data:
1, COUNT(B 1, D 1) is to calculate how many numbers are in cells B 1 and D 1 (excluding cell C 1).
2.COUNT(B 1:D 1) is the number of digits from cell B 1 to cell D 1 (including cell C 1).
3. Count ("B 1", "D 1", "123" and "Hello"), and the result is 1, because there is only one number, B 1 and d/kloc-0.
Baidu encyclopedia-counting function