Welcome to MySQL Workbench:MySQL 字符串函数CHAR_LENGTH(pro)
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内容图文
CHAR_LENGTH(pro):
返回字符串 pro 的字符数
CREATE TABLE test_NO1(
test_NO1_id INT NOT NULL AUTO_INCREMENT,
test_NO1_title VARCHAR(100) NOT NULL,
test_NO1_author VARCHAR(40) NOT NULL,
test_NO1_date DATE,
PRIMARY KEY ( test_NO1_id )
)ENGINE=InnoDB;
drop table test_no1;
INSERT INTO test_NO1
(test_NO1_title, test_NO1_author, test_NO1_date )
VALUES
("programb", "welcome to programb", NOW());
select * from test_NO1;
INSERT INTO test_NO1
(test_NO1_title, test_NO1_author, test_NO1_date )
VALUES
("programb2", "welcome to programb2", NOW());
INSERT INTO test_NO1
(test_NO1_title, test_NO1_author, test_NO1_date )
VALUES
("programb3", "welcome to programb3", NOW());
SELECT * from test_NO1 WHERE test_NO1_title='programb2';
SELECT * from test_NO1;
update test_NO1 SET test_NO1_title='programb100' WHERE test_NO1_id=1;
SELECT * from test_NO1 where test_NO1_id=1;
SELECT * from test_NO1;
DELETE FROM test_NO1 WHERE test_NO1_id=1;
SELECT * from test_NO1;
SELECT * from test_NO1 WHERE test_NO1_title LIKE '%programb2';
INSERT INTO test_NO1
(test_NO1_title, test_NO1_author, test_NO1_date )
VALUES
("programb2", "welcome.to.programb2", NOW());
SELECT * from test_NO1 WHERE test_NO1_author LIKE '%programb2';
SELECT * from test_NO1 WHERE test_NO1_author LIKE '%to%';
SELECT * from test_NO1 WHERE test_NO1_author LIKE 'welcome%';
SELECT * from test_NO1;
CREATE TABLE test_NO2(
test_NO1_id INT NOT NULL AUTO_INCREMENT,
test_NO1_title VARCHAR(100) NOT NULL,
test_NO1_author VARCHAR(40) NOT NULL,
test_NO1_date DATE,
PRIMARY KEY ( test_NO1_id )
)ENGINE=InnoDB;
INSERT INTO test_NO2
(test_NO1_title, test_NO1_author, test_NO1_date )
VALUES
("programb2", "welcome.to.programb2", NOW());
SELECT * from test_NO2;
SELECT test_NO1_author FROM test_no1
UNION
SELECT test_NO1_author FROM test_no2
ORDER BY test_NO1_author;
SELECT test_NO1_author FROM test_no1
UNION all
SELECT test_NO1_author FROM test_no2
ORDER BY test_NO1_author;
select * from test_no1 order by test_NO1_date asc;
INSERT INTO test_NO1
(test_NO1_title, test_NO1_author, test_NO1_date )
VALUES
("programb4", "welcome to programb4", NOW());
INSERT INTO test_NO1
(test_NO1_title, test_NO1_author, test_NO1_date )
VALUES
("programb5", "welcome to programb5", NOW());
select * from test_no1 order by test_NO1_date asc;
select * from test_no1 order by test_NO1_date desc;
select test_NO1_title, count(*) from test_no1 group by test_NO1_title;
select test_NO1_title, sum(test_NO1_id) from test_no1 group by test_NO1_title;
select test_NO1_title, avg(test_NO1_id) from test_no1 group by test_NO1_title;
SELECT * from test_NO1;
SELECT * from test_no2;
INSERT INTO test_NO2
(test_NO1_title, test_NO1_author, test_NO1_date )
VALUES
("programb4", "welcome to programb4", NOW());
INSERT INTO test_NO2
(test_NO1_title, test_NO1_author, test_NO1_date )
VALUES
("programb2", "welcome to programb2", NOW());
SELECT * from test_no2;
select t1.test_NO1_title, t2.test_NO1_date from test_no1 t1, test_no2 t2 where t1.test_NO1_date=t2.test_NO1_date;
select t1.test_NO1_title, t2.test_NO1_date from test_no1 t1 left join test_no2 t2 on t1.test_NO1_date=t2.test_NO1_date;
select t1.test_NO1_title, t2.test_NO1_date from test_no1 t1 right join test_no2 t2 on t1.test_NO1_date=t2.test_NO1_date;
SELECT * from test_no2;
INSERT INTO test_NO2
(test_NO1_title, test_NO1_author, test_NO1_date )
VALUES
("programb2", "welcome", NOW());
SELECT * from test_no2;
select * from test_no2 where test_NO1_author is null;
INSERT INTO test_NO2
(test_NO1_title, test_NO1_author )
VALUES
("programb2", "welcome");
INSERT INTO test_NO2
(test_NO1_title, test_NO1_author )
VALUES
("programb2", "welcome");
INSERT INTO test_NO2
(test_NO1_title, test_NO1_author )
VALUES
("programb2", "welcome");
SELECT * from test_no2;
select * from test_no2 where test_NO1_date is null;
select * from test_no2 where test_NO1_date is not null;
select * from test_no1 where test_NO1_title regexp '^pro';
select * from test_no1 where test_NO1_title regexp '2$';
select * from test_no1 where test_NO1_title regexp 'gra';
select * from test_no1 where test_NO1_title regexp '^[pro]|5$';
begin;
insert into test_NO1(test_NO1_title, test_NO1_author ) value("pro","welcome");
insert into test_NO1(test_NO1_title, test_NO1_author ) value("pro","welcome");
insert into test_NO1(test_NO1_title, test_NO1_author ) value("pro","welcome");
insert into test_NO1(test_NO1_title, test_NO1_author ) value("pro","welcome");
insert into test_NO1(test_NO1_title, test_NO1_author ) value("pro","welcome");
insert into test_NO1(test_NO1_title, test_NO1_author ) value("pro","welcome");
commit;
SELECT * from test_NO1;
show columns from test_no1;
alter table test_no1 alter test_NO1_author set default 1000;
alter table test_no1 modify test_NO1_author varchar(100);
show columns from test_no1;
alter table test_no1 drop test_NO1_author;
show columns from test_no1;
alter table test_no1 add test_NO1_author int first;
show columns from test_no1;
alter table test_no1 drop test_NO1_author;
alter table test_no1 add test_NO1_author int;
show columns from test_no1;
alter table test_no1 drop test_NO1_author;
alter table test_no1 add test_NO1_author varchar(100);
CREATE TABLE test_no3(ID INT NOT NULL,username VARCHAR(16) NOT NULL, INDEX username2 (username(12)));
show columns from test_no3;
SELECT * from test_no3;
select username from test_no3;
SHOW INDEX FROM test_no3;
DROP INDEX username2 ON test_no3;
SHOW INDEX FROM test_no3;
ALTER TABLE test_no3 ADD INDEX (username);
ALTER TABLE test_no3 DROP INDEX username;
CREATE TEMPORARY TABLE test_no4 (test_name VARCHAR(50) NOT NULL);
select * from test_no4;
DROP TABLE test_no4;
INSERT INTO test_no4 (test_name)VALUES(1000000);
select * from test_no3;
SHOW CREATE TABLE test_no3;
INSERT INTO test_no3 (id,username)VALUES(1,1000000);
select * from test_no3;
CREATE TABLE test_no5 (id int ,username VARCHAR(50) NOT NULL);
INSERT INTO test_no5(id,username)SELECT id,username FROM test_no3;
select * from test_no5;
SELECT VERSION();
SELECT USER();
SELECT DATABASE();
SHOW STATUS;
SHOW VARIABLES;
CREATE TABLE test_no6(id INT UNSIGNED NOT NULL AUTO_INCREMENT,PRIMARY KEY (id),name VARCHAR(30) NOT NULL);
INSERT INTO test_no6 (id,name)values(null,'1001');
INSERT INTO test_no6 (id,name)values(null,'1002');
INSERT INTO test_no6 (id,name)values(null,'1003');
INSERT INTO test_no6 (id,name)values(null,'1004');
INSERT INTO test_no6 (id,name)values(null,'1005');
INSERT INTO test_no6 (id,name)values(null,'1006');
INSERT INTO test_no6 (id,name)values(null,'1007');
SELECT * FROM test_no6 ORDER BY id;
CREATE TABLE test_no7(first_name CHAR(20),last_name CHAR(20),sex CHAR(10));
CREATE TABLE test_no8(first_name CHAR(20) NOT NULL,last_name CHAR(20) NOT NULL,sex CHAR(10),PRIMARY KEY (last_name, first_name));
CREATE TABLE test_no9(first_name CHAR(20) NOT NULL,last_name CHAR(20) NOT NULL,sex CHAR(10),UNIQUE (last_name, first_name));
SELECT * FROM test_no1 INTO OUTFILE 'f:\ddd.txt';
SELECT ASCII(test_NO1_title) AS test_NO1_title FROM test_no1;
select * from test_no1;
SELECT CHAR_LENGTH("test_NO1_title") AS test_NO1_title;
SELECT CHAR_LENGTH("test_NO1_title") AS test_NO1_title;
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