INSERT INTO bookcategory(category_id,category,parent_id) VALUES(1,‘計算機‘,0);//指定插入的順序


INSERT INTO bookcategory VALUES(1,‘計算機‘,0);//按照默認的插入


INSERT INTO bookcategory(category_id,category,parent_id) VALUES(1,‘計算機‘,0)，(2,‘xxx‘,3)(3,‘xxxxx‘,4);//同時插入多條數據


INSERT INTO bookcategory SELECT * FROM test WHERE id>5
 
//將查詢結果插入表中


CREATE TABLE TEXT(

    category_id INT PRIMARY KEY AUTO_INCREMENT,

    parent_id INT NOT NULL

)AUTO_INCREMENT=5;    //auto_increment讓這一列自動設置編號，默認初始值為,最後為設置初始值為5



ALTER TABLE bookcategory MODIFY category_id INT AUTO_INCREMENT=X//為已有表添加自增列



ALTER TABLE bookcategory MODIFY category_id INT;//去掉自增列


//有外鍵關系的話添加自增，要先去掉外鍵關系。


 
ALTER TABLE bookinfo DROP FOREIGN KEY fk_bcid//去掉外鍵


ALTER TABLE bookinfo ADD CONSTRAINT fk_bcid FOREIGN KEY(bookcdategory_id) REFERENCES bookcategory(category_id);//添加外鍵


SELECT price FROM bookinfo WHERE book_id=201501;//查詢book_id為201501書的價格


SELECT * FROM readerinfo//查看讀者信息表


SELECT xxx,xxx,xxx FROM readerinfo//查詢指定列


 
SELECT xxx,xxx,xxx FROM readerinfo WHERE press=‘機械工業‘//設置外加條件的查詢


SELECT DISTINCT press FROM bookinfo;//顯示不重復的查詢


SELECT * FROM readerinfo WHERE age IS NULL;//查詢為空的列


UPDATE readerinfo SET balance =balance -18.9*0.05 WHERE card_id=‘xxxxxxxx‘//更新readerinfo這個表中的card_id為xxx的balance


DELETE FROM readerinfo WHERE card_id=‘201531513133‘//單表數據記錄的刪除,不加where則為全部刪除


TRUNCATE TABLE readerinfo;//刪除原表再創建空表


SELECT COUNT(*) FROM readerinfo WHERE sex=‘男‘//對查詢結果的分組


SELECT sex FROM readerinfo GROUP BY sex;//查詢有多少種性別


SELECT sex COUNT(*) FROM readerinfo GROUP BY sex;//統計每種性別的人數


SELECT sex FROM readerinfo GROUP BY sex WHERE COUNT(sex)>3;//也可以加限制條件。統計每種性別的人數


SELECT     * FROM bookinfo ORDER BY price//對查詢結果排序，默認為升序


SELECT     * FROM bookinfo ORDER BY price,store;//price相同的，按照庫存排序


SELECT * FROM bookinfo ORDER BY price ASC,store DESC;//asc升序，desc降序


SELECT * FROM bookinfo LIMIT 3;//limit限制查詢數量，偏移量為0開始,顯示前三行


SELECT * FROM bookinfo LIMIT 2,2;//顯示第二條語句的後兩個語句


SELECT store,COUNT(*) FROM bookinfo GROUP BY store ORDER BY store DESC LIMIT 4;//統計庫存個數，並降序排序，並查看前四條語句

INSERT INTO bookcategory(category_id,category,parent_id) VALUES(1,‘計算機‘,0);//指定插入的順序
INSERT INTO bookcategory VALUES(1,‘計算機‘,0);//按照默認的插入
INSERT INTO bookcategory(category_id,category,parent_id) VALUES(1,‘計算機‘,0)，(2,‘xxx‘,3)(3,‘xxxxx‘,4);//同時插入多條數據
INSERT INTO bookcategory SELECT * FROM test WHERE id>5//將查詢結果插入表中
CREATE TABLE TEXT(
category_id INT PRIMARY KEY AUTO_INCREMENT,
parent_id INT NOT NULL
)AUTO_INCREMENT=5; //auto_increment讓這一列自動設置編號，默認初始值為,最後為設置初始值為5
ALTER TABLE bookcategory MODIFY category_id INT AUTO_INCREMENT=X//為已有表添加自增列
ALTER TABLE bookcategory MODIFY category_id INT;//去掉自增列
//有外鍵關系的話添加自增，要先去掉外鍵關系。
ALTER TABLE bookinfo DROP FOREIGN KEY fk_bcid//去掉外鍵
ALTER TABLE bookinfo ADD CONSTRAINT fk_bcid FOREIGN KEY(bookcdategory_id) REFERENCES bookcategory(category_id);//添加外鍵
SELECT price FROM bookinfo WHERE book_id=201501;//查詢book_id為201501書的價格
SELECT * FROM readerinfo//查看讀者信息表
SELECT xxx,xxx,xxx FROM readerinfo//查詢指定列
SELECT xxx,xxx,xxx FROM readerinfo WHERE press=‘機械工業‘//設置外加條件的查詢
SELECT DISTINCT press FROM bookinfo;//顯示不重復的查詢
SELECT * FROM readerinfo WHERE age IS NULL;//查詢為空的列
UPDATE readerinfo SET balance =balance -18.9*0.05 WHERE card_id=‘xxxxxxxx‘//更新readerinfo這個表中的card_id為xxx的balance
DELETE FROM readerinfo WHERE card_id=‘201531513133‘//單表數據記錄的刪除,不加where則為全部刪除
TRUNCATE TABLE readerinfo;//刪除原表再創建空表
SELECT COUNT(*) FROM readerinfo WHERE sex=‘男‘//對查詢結果的分組
SELECT sex FROM readerinfo GROUP BY sex;//查詢有多少種性別
SELECT sex COUNT(*) FROM readerinfo GROUP BY sex;//統計每種性別的人數
SELECT sex FROM readerinfo GROUP BY sex WHERE COUNT(sex)>3;//也可以加限制條件。統計每種性別的人數
SELECT * FROM bookinfo ORDER BY price//對查詢結果排序，默認為升序
SELECT * FROM bookinfo ORDER BY price,store;//price相同的，按照庫存排序
SELECT * FROM bookinfo ORDER BY price ASC,store DESC;//asc升序，desc降序
SELECT * FROM bookinfo LIMIT 3;//limit限制查詢數量，偏移量為0開始,顯示前三行
SELECT * FROM bookinfo LIMIT 2,2;//顯示第二條語句的後兩個語句
SELECT store,COUNT(*) FROM bookinfo GROUP BY store ORDER BY store DESC LIMIT 4;//統計庫存個數，並降序排序，並查看前四條語句

mysql的學習（四）-數據庫表的記錄的操作