SQL 语句详解

最新推荐文章于 2021-06-20 21:53:36 发布

原创最新推荐文章于 2021-06-20 21:53:36 发布 · 319 阅读

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SQL 语句详解

/* CREATE TABLE IF NOT EXISTS t_student (name text, age integer); */

/* INSERT INTO t_student (name, age) VALUES ('xiaoming', 13); */

/* UPDATE t_student SET age = 24 WHERE name = 'xiaoming'; */

/* DROP TABLE IF EXISTS t_student;*/

CREATE TABLE IF NOT EXISTS t_student (id integer PRIMARY KEY AUTOINCREMENT, name text, age integer);

/* INSERT INTO t_student (name, age) VALUES ('xiaoming', 213); */

/* UPDATE t_student SET age = 23 WHERE name = 'xiaoming'; */

/* DELETE FROM t_student WHERE name = 'xiaohua'; */

/*
INSERT INTO t_student (name) VALUES ('xiaozhang');
INSERT INTO t_student (name) VALUES ('xiaowang');
INSERT INTO t_student (name) VALUES ('xiaoyi');
INSERT INTO t_student (name) VALUES ('jack');
INSERT INTO t_student (name) VALUES ('kitty');
*/

/*
INSERT INTO t_student (name ,age) VALUES ('xiaozhang', 23);
INSERT INTO t_student (name ,age) VALUES ('jj', 23);
INSERT INTO t_student (name ,age) VALUES ('33', 23);
INSERT INTO t_student (name ,age) VALUES ('44', 23);
*/

/* SELECT * FROM t_student WHERE age > 21 */

/*
INSERT INTO t_student (name, age) VALUES ('xiaoyi', 21);
INSERT INTO t_student (name, age) VALUES ('xiaoyi', 22);
INSERT INTO t_student (name, age) VALUES ('xiaoyi', 23);
INSERT INTO t_student (name, age) VALUES ('xiaoyi', 24);
INSERT INTO t_student (name, age) VALUES ('xiaoyi', 25);
INSERT INTO t_student (name, age) VALUES ('xiaoyi', 26);
*/

/* SELECT * FROM t_student t WHERE t.name = 'xiaoyi' AND t.age NOTNULL ORDER BY age DESC;*/

/* SELECT s.age student_age, s.name student_name FROM t_student s; */

/* SELECT age, name FROM t_student WHERE name LIKE '%xiao%';*/

/* SELECT * FROM t_persion WHERE class = (SELECT id FROM t_class WHERE name = '二班'); */

SELECT * FROM t_persion p, t_class c WHERE p.class = c.id AND c.name = '一班';