SQLite - COUNT语句

SELECT COUNT(aggregate_expression)
FROM tables
[WHERE conditions]; 

SELECT expression1, expression2, ... expression_n
COUNT(aggregate_expression)
FROM tables
[WHERE conditions]
GROUP BY expression1, expression2, ... expression_n; 

SELECT COUNT(*) AS "Number of students"
FROM STUDENT
WHERE AGE > 22;

SELECT NAME, COUNT(*) AS "Number Of Students"
FROM STUDENT
WHERE AGE > 22
GROUP BY NAME;