# 第12章_MySQL数据类型精讲
# 本章的内容测试建议使用 MySQL5.7进行测试。

# 1. 关于属性：character set name

SHOW VARIABLES LIKE 'character_%';

#创建数据库时指明字符集
CREATE DATABASE IF NOT EXISTS dbtest12 CHARACTER SET 'utf8';

SHOW CREATE DATABASE dbtest12;

#创建表的时候，指明表的字符集
CREATE TABLE temp(
    id INT
) CHARACTER SET 'utf8';

SHOW CREATE TABLE temp;

#创建表，指明表中的字段时，可以指明字段的字符集
CREATE TABLE temp1(
    id INT,
    name VARCHAR(15) CHARACTER SET 'gbk'
);

SHOW CREATE TABLE temp1;

# 2. 整形数据类型

USE dbtest12;

CREATE TABLE test_int1(
    f1 TINYINT,
    f2 SMALLINT,
    f3 MEDIUMINT,
    f4 INTEGER,
    f5 BIGINT
);

DESC test_int1;

INSERT INTO test_int1(f1)
VALUES (12),(-12),(-128),(127);

SELECT * FROM test_int1;

# Out of range value for column 'f1' at row 1
INSERT INTO test_int1(f1)
VALUES(128);

CREATE TABLE test_int2(
    f1 INT,
    f2 INT(5),
    f3 INT(5) ZEROFILL  #① 显示宽度为5。当INSERT的值不足5位时，使用0填充。② 当使用ZEROFILL时，自动会添加UNSIGNED
);

INSERT INTO test_int2(f1,f2)
VALUES(123,123),(123456,123456);

SELECT * FROM test_int2;

INSERT INTO test_int2(f3)
VALUES(123),(123456);

SHOW CREATE TABLE test_int2;

CREATE TABLE test_int3(
    f1 INT UNSIGNED
);

DESC test_int3;

INSERT INTO test_int3
VALUES(2412321);

INSERT INTO test_int3
VALUES(4294967296);

# 3. 浮点类型
CREATE TABLE test_double1(
    f1 FLOAT,
    f2 FLOAT(5,2),
    f3 DOUBLE,
    f4 DOUBLE(5,2)
);

DESC test_double1;

INSERT INTO test_double1(f1,f2)
VALUES(123.45,123.45);

SELECT * FROM test_double1;

INSERT INTO test_double1(f3,f4)
VALUES(123.45,123.456); #存在四舍五入

# Out of range value for column 'f4' at row 1
INSERT INTO test_double1(f3,f4)
VALUES(123.45,1234.456);

# Out of range value for column 'f4' at row 1
INSERT INTO test_double1(f3,f4)
VALUES(123.45,999.995);

#测试FLOAT和DOUBLE的精度问题
CREATE TABLE test_double2(
f1 DOUBLE
);

INSERT INTO test_double2
VALUES(0.47),(0.44),(0.19);

SELECT SUM(f1)
FROM test_double2;

SELECT SUM(f1) = 1.1,1.1 = 1.1
FROM test_double2;

# 4. 定点数类型
CREATE TABLE test_decimal1(
    f1 DECIMAL,
    f2 DECIMAL(5,2)
);

DESC test_decimal1;

INSERT INTO test_decimal1(f1)
VALUES(123),(123.45);

SELECT * FROM test_decimal1;

INSERT INTO test_decimal1(f2)
VALUES(999.99);

INSERT INTO test_decimal1(f2)
VALUES(67.567); #存在四舍五入

# Out of range value for column 'f2' at row 1
INSERT INTO test_decimal1(f2)
VALUES(1267.567);

# Out of range value for column 'f2' at row 1
INSERT INTO test_decimal1(f2)
VALUES(999.9995);

#演示DECIMAL替换DOUBLE, 体现精度
ALTER TABLE test_double2
MODIFY f1 DECIMAL(5,2);

DESC test_double2;

SELECT SUM(f1)
FROM test_double2;

SELECT SUM(f1) = 1.1,1.1 = 1.1
FROM test_double2;

# 5. 位类型：BIT
CREATE TABLE test_bit1(
f1 BIT,
f2 BIT(5),
f3 BIT(64)
);

DESC test_bit1;

INSERT INTO test_bit1(f1)
VALUES(0),(1);

SELECT *
FROM test_bit1;

# Data too long for column 'f1' at row 1
INSERT INTO test_bit1(f1)
VALUES(2);

INSERT INTO test_bit1(f2)
VALUE(31);

# Data too long for column 'f1' at row 1
INSERT INTO test_bit1(f2)
VALUE(32);

SELECT BIN(f1),BIN(f2),HEX(f1),HEX(f2)
FROM test_bit1;

#此时+0以后，可以以十进制的方式显式数据
SELECT f1 + 0, f2 + 0
FROM test_bit1;

# 6.1 YEAR类型
CREATE TABLE test_year(
    f1 YEAR,
    f2 YEAR(4)
);

DESC test_year;

INSERT INTO test_year(f1)
VALUES('2021'),(2022);

SELECT * FROM test_year;

INSERT INTO test_year(f1)
VALUES ('2155');

# Out of range value for column 'f1' at row 1
INSERT INTO test_year(f1)
VALUES ('2156');

INSERT INTO test_year(f1)
VALUES ('69'),('70');

INSERT INTO test_year(f1)
VALUES (0),('00');

# 6.2 DATE类型

CREATE TABLE test_date1(
    f1 DATE
);

DESC test_date1;

INSERT INTO test_date1
VALUES ('2020-10-01'), ('20201001'),(20201001);

INSERT INTO test_date1
VALUES ('00-01-01'), ('000101'), ('69-10-01'), ('691001'), ('70-01-01'), ('700101'),('99-01-01'), ('990101');

INSERT INTO test_date1
VALUES (000301), (690301), (700301), (990301);  #存在隐式转换

INSERT INTO test_date1
VALUES (CURDATE()),(CURRENT_DATE()),(NOW());

SELECT *
FROM test_date1;

# 6.3 TIME类型
CREATE TABLE test_time1(
    f1 TIME
);

DESC test_time1;

INSERT INTO test_time1
VALUES('2 12:30:29'), ('12:35:29'), ('12:40'), ('2 12:40'),('1 05'), ('45');

INSERT INTO test_time1
VALUES ('123520'), (124011),(1210);

INSERT INTO test_time1
VALUES (NOW()), (CURRENT_TIME()),(CURTIME());

SELECT *
FROM test_time1;

# 6.4 DATETIME类型
CREATE TABLE test_datetime1(
    dt DATETIME
);

INSERT INTO test_datetime1
VALUES ('2021-01-01 06:50:30'), ('20210101065030');

INSERT INTO test_datetime1
VALUES ('99-01-01 00:00:00'), ('990101000000'), ('20-01-01 00:00:00'),('200101000000');

INSERT INTO test_datetime1
VALUES (20200101000000), (200101000000), (19990101000000), (990101000000);

INSERT INTO test_datetime1
VALUES (CURRENT_TIMESTAMP()), (NOW());

SELECT *
FROM test_datetime1;

# 6.5 TIMESTAMP类型
CREATE TABLE test_timestamp1(
    ts TIMESTAMP
);

INSERT INTO test_timestamp1
VALUES ('1999-01-01 03:04:50'), ('19990101030405'), ('99-01-01 03:04:05'),('990101030405');

INSERT INTO test_timestamp1
VALUES ('2020@01@01@00@00@00'), ('20@01@01@00@00@00');

INSERT INTO test_timestamp1
VALUES (CURRENT_TIMESTAMP()), (NOW());

#Incorrect datetime value
INSERT INTO test_timestamp1
VALUES ('2038-01-20 03:14:07');

SELECT *
FROM test_timestamp1;

#对比DATETIME 和 TIMESTAMP
CREATE TABLE temp_time(
    d1 DATETIME,
    d2 TIMESTAMP
);

INSERT INTO temp_time VALUES('2021-9-2 14:45:52','2021-9-2 14:45:52');

INSERT INTO temp_time VALUES(NOW(),NOW());

SELECT * FROM temp_time;

#修改当前的时区
SET time_zone = '+9:00';

SELECT * FROM temp_time;

# 7.1 CHAR类型
CREATE TABLE test_char1(
    c1 CHAR,
    c2 CHAR(5)
);

DESC test_char1;

INSERT INTO test_char1(c1)
VALUES('a');

# Data too long for column 'c1' at row 1
INSERT INTO test_char1(c1)
VALUES('ab');

INSERT INTO test_char1(c2)
VALUES('ab');

INSERT INTO test_char1(c2)
VALUES('hello');

INSERT INTO test_char1(c2)
VALUES('尚');

INSERT INTO test_char1(c2)
VALUES('硅谷');

INSERT INTO test_char1(c2)
VALUES('尚硅谷教育');

# Data too long for column 'c2' at row 1
INSERT INTO test_char1(c2)
VALUES('尚硅谷IT教育');

SELECT * FROM test_char1;

SELECT CONCAT(c2,'***')
FROM test_char1;

INSERT INTO test_char1(c2)
VALUES('ab  ');

SELECT CHAR_LENGTH(c2)
FROM test_char1;

# 7.2 VARCHAR类型
CREATE TABLE test_varchar1(
    name VARCHAR    #错误
);

# Column length too big for column 'name' (max = 21845); use BLOB or TEXT instead
CREATE TABLE test_varchar2(
    name VARCHAR(65535)
);

CREATE TABLE test_varchar3(
NAME VARCHAR(5)
);

INSERT INTO test_varchar3
VALUES('尚硅谷'),('尚硅谷教育');

#Data too long for column 'NAME' at row 1
INSERT INTO test_varchar3
VALUES('尚硅谷IT教育');

# 7.3 TEXT类型
CREATE TABLE test_text(
    tx TEXT
);

INSERT INTO test_text
VALUES('atguigu   ');

SELECT CHAR_LENGTH(tx)
FROM test_text; #10

# 8. ENUM类型
CREATE TABLE test_enum(
    season ENUM('春','夏','秋','冬','unknow')
);

INSERT INTO test_enum
VALUES('春'),('秋');

SELECT * FROM test_enum;

# Data truncated for column 'season' at row 1
INSERT INTO test_enum
VALUES('春,秋');
# Data truncated for column 'season' at row 1
INSERT INTO test_enum
VALUES('人');

INSERT INTO test_enum
VALUES('unknow');

#忽略大小写的
INSERT INTO test_enum
VALUES('UNKNOW');

#可以使用索引进行枚举元素的调用
INSERT INTO test_enum
VALUES(1),('3');

#没有限制非空的情况下，可以添加null值
INSERT INTO test_enum
VALUES(NULL);

# 9. SET类型
CREATE TABLE test_set(
    s SET ('A','B','C')
);

INSERT INTO test_set (s) VALUES ('A'), ('A,B');

#插入重复的SET类型成员时，MySQL会自动删除重复的成员
INSERT INTO test_set (s) VALUES ('A,B,C,A');

#向SET类型的字段插入SET成员中不存在的值时，MySQL会抛出错误。
INSERT INTO test_set (s) VALUES ('A,B,C,D');

SELECT *
FROM test_set;

CREATE TABLE temp_mul(
gender ENUM('男','女'),
hobby SET('吃饭','睡觉','打豆豆','写代码')
);

INSERT INTO temp_mul
VALUES('男','睡觉,打豆豆');

SELECT *
FROM temp_mul;

# Data truncated for column 'gender' at row 1
INSERT INTO temp_mul
VALUES('男,女','睡觉,打豆豆');

# 10.1 BINARY 与 VARBINARY类型
CREATE TABLE test_binary1(
    f1 BINARY,
    f2 BINARY(3),
#     f3 VARBINARY,
    f4 VARBINARY(10)
);

DESC test_binary1;

INSERT INTO test_binary1(f1,f2)
VALUES('a','abc');

SELECT * FROM test_binary1;

# Data too long for column 'f1' at row 1
INSERT INTO test_binary1(f1)
VALUES('ab');

INSERT INTO test_binary1(f2,f4)
VALUES('ab','ab');

SELECT LENGTH(f2),LENGTH(f4)
FROM test_binary1;

# 10.2 Blob类型
CREATE TABLE test_blob1(
    id INT,
    img MEDIUMBLOB
);

INSERT INTO test_blob1(id)
VALUES (1001);

SELECT *
FROM test_blob1;

# 11. JSON类型
CREATE TABLE test_json(
    js JSON
);

INSERT INTO test_json (js)
VALUES ('{"name":"songhk", "age":18, "address":{"province":"beijing",
"city":"beijing"}}');

SELECT * FROM test_json;

SELECT js -> '$.name' AS NAME,js -> '$.age' AS age ,js -> '$.address.province'AS province, js -> '$.address.city' AS city
FROM test_json;