sqilite学习

1,用代码插入数据

for (int i = 0; i < 100; i++) {
        NSString *nameStr = [NSString stringWithFormat:@"mingyueixn-%d",arc4random_uniform(100)];
        NSString *sqlStr = [NSString stringWithFormat:@"INSERT INTO t_student (name,idstr,age,score) VALUES ('%@',%d,%d,%.2f);",nameStr,201000+i +1,(arc4random_uniform(10) + 17),(arc4random_uniform(400) + 600)/10.0];
        printf("%s\n",sqlStr.UTF8String);
    }
2,删除表

DROP TABLE IF EXITS t_student;

3,删除所有数据

DELETE FROM t_student;

4,删除特定的数据->条件限制

DELETE FROM t_student WHERE score < 80;

5,查询 80-90

SELECT *FROM t_student WHERE score > 80 AND score < 90;

6,查询的数据排序

SELECT *FROM t_student WHERE score > 80 AND score < 90 ORDER BY score;

7,SELECT *FROM t_student WHERE score > 80 AND score < 90 ORDER BY score ASC;//升序排.DESC倒序排

8, SELECT *FROM t_student ORDER BY age, score DESC;