gunsmoke的专栏

需求 建表语句 CREATE TABLE Greatests (key1 CHAR(1) PRIMARY KEY, x INTEGER NOT NULL, y INTEGER NOT NULL, z INTEGER NOT NULL); INSERT INTO Greatests VALUES('A', 1, 2, 3); INSERT INTO Greatests VALUES('B', 5, 5, 2); INSERT INTO Greatests VALUES('C', 4,

需求 建表语句 CREATE TABLE CourseMaster (course_id INTEGER PRIMARY KEY, course_name VARCHAR(32) NOT NULL); INSERT INTO CourseMaster VALUES(1, '会计入门'); INSERT INTO CourseMaster VALUES(2, '财务知识'); INSERT INTO CourseMaster VALUES(3, '簿记考试'); INSERT INTO Course

需求 解法 update salaries set salary = CASE WHEN salary >= 300000 THEN salary * 0.9 WHEN salary >250000 and salary < 280000 then salary * 1.2 ELSE salary END

需求 建表语句 CREATE TABLE PopTbl2 (pref_name VARCHAR(32), sex CHAR(1) NOT NULL, population INTEGER NOT NULL, PRIMARY KEY(pref_name, sex)); INSERT INTO PopTbl2 VALUES('德岛', '1', 60 ); INSERT INTO PopTbl2 VALUES('德岛', '2', 40 ); INSERT INTO PopTbl2 VALUES

需求 建表语句 /* 将已有编号方式转换为新的方式并统计 */ CREATE TABLE PopTbl (pref_name VARCHAR(32) PRIMARY KEY, population INTEGER NOT NULL); INSERT INTO PopTbl VALUES('德岛', 100); INSERT INTO PopTbl VALUES('香川', 200); INSERT INTO PopTbl VALUES('爱媛', 150); INSERT INTO PopTbl VA