CREATE TABLE students (
    id INTEGER PRIMARY KEY AUTOINCREMENT, -- 自動連番に設定
    name TEXT NOT NULL,
    gender TEXT NOT NULL,
    age INTEGER NOT NULL
);

-- IDを指定せず（またはNULLで）INSERTする
INSERT INTO students (name, gender, age) VALUES ('いちの','♂',13);
INSERT INTO students (name, gender, age) VALUES ('いとう','♀',13);
INSERT INTO students (name, gender, age) VALUES ('おおすが','♂',13);
INSERT INTO students (name, gender, age) VALUES ('おおた','♂',13);
INSERT INTO students (name, gender, age) VALUES ('おおやま','♂',13);
INSERT INTO students (name, gender, age) VALUES ('かとう','♀',13);
INSERT INTO students (name, gender, age) VALUES ('かわの','♂',13);
INSERT INTO students (name, gender, age) VALUES ('かわはら','♂',13);

SELECT * FROM students WHERE gender = '♂';