文章分类 - 数据库
摘要:SELECT member.regName,city.regname FROM member RIGHT JOIN city on member.regName=city.regname;
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摘要:内连接显示左表右表符合条件的记录 INSERT JSON 左外链接 LEFT JSON 显示左表的所有数据,右表没有数据显示null 右外链接 RIGHT JSON 显示右表的所有数据,左表没有数据显示null
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摘要:SELECT ti.age,t2.regname from member ti,city t2 WHERE ti.regName=t2.regname;
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摘要:根据字段分组,分组后对组内数据进行运算 SELECT COunt(regName) FROM member GROUP BY sex;
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摘要:select DISTINCT regName from member ; 统计去重后数据 select COUNT(DISTINCT regName) from member ;
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摘要:select * from city WHERE monry BETWEEN 20 AND 50;
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摘要:模糊查询 select * from member WHERE regName LIKE '王%';
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摘要:查询两个表根据关联的信息查询 1.SELECT * FROM member,mon WHERE member.regName=mon.regname; 查询两个表根据关联的信息查询查询表头重命名 2.SELECT member.regName AS注册名,mon.money AS 余额 FROM m
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摘要:查询所有字段值 SELECT * FROM member; 查询指定字段 SELECT regName FROM member; 条件查询 SELECT regName,mobilePhone FROM member WHERE regName='qq'AND pwd=123456; 将查询的数据字
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摘要:修改表改字段所有数据 UPDATE member SET regName = 'qq';,将用户名都更改; 更改指定的数据 UPDATE member SET regName = 'ww' WHERE regName='kk';
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摘要:删除指定数据 DELETE from member WHERE regName = 'huididi'; 删除所有数据 DELETE FROM regName;不会重建id,id会继续增加 TRUNCATE FROM member;会重建id,id会从1开始
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摘要:插入行所有数据 1.INSERT INTO member VALUES(5,'wangkai','123456','15313929271',1,0,'2020-05-17 14:00:00'); 插入行指定列 2.INSERT INTO member (id,regName) VALUES(6,'
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