MySQL - FLOAT 浮点数据类型

要通过 JavaScript 程序创建浮点型列，我们需要使用 mysql2 库的 query() 函数执行"CREATE TABLE"语句，如下所示 -

sql = "CREATE TABLE temp(Id INT AUTO_INCREMENT, Celsius FLOAT, Fahrenheit FLOAT, PRIMARY KEY(Id))";
con.query(sql);

要通过 Java 程序创建浮点型数据类型的列，我们需要使用 JDBC 函数 execute() 执行"CREATE TABLE"语句，如下所示 -

String sql = "CREATE TABLE temp(Id INT AUTO_INCREMENT, Celsius FLOAT, Fahrenheit FLOAT, PRIMARY KEY(Id))";
statement.execute(sql);

要通过 Python 程序创建浮点型数据类型的列，我们需要使用 MySQL Connector/Python 的 execute() 函数执行"CREATE TABLE"语句，如下所示 -

sql = 'CREATE TABLE datatype_demo(ID INT, NAME VARCHAR(50), HEIGHT FLOAT, WEIGHT FLOAT)''
cursorObj.execute(sql)

var mysql = require("mysql2");
var con = mysql.createConnection({
  host: "localhost",
  user: "root",
  password: "password",
}); //连接到 MySQL

con.connect(function (err) {
  if (err) throw err;
  //   console.log("Connected successfully...!");
  //   console.log("--------------------------");
  sql = "USE TUTORIALS";
  con.query(sql);
 //创建一个student表，它接受一列float类型。
  sql =
    "CREATE TABLE temp(Id INT AUTO_INCREMENT, Celsius FLOAT, Fahrenheit FLOAT, PRIMARY KEY(Id))";
  con.query(sql);
 //将数据插入到创建的表中
  sql =
    "INSERT INTO temp(Celsius, Fahrenheit) VALUES ( 36.2, 97.16), ( 35.8, 96.44), ( 37.32, 99.17), ( 35.89, 96.602)";
  con.query(sql);
  //select datatypes of salary
  sql = `SELECT DATA_TYPE FROM INFORMATION_SCHEMA.COLUMNS WHERE table_name = 'temp' AND COLUMN_NAME = 'Celsius'`;
  con.query(sql, function (err, result) {
    if (err) throw err;
    console.log(result);
  });
});       

输出

生成的输出如下 -

[ { DATA_TYPE: 'float' } ]

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class Float {
   public static void main(String[] args) {
      String url = "jdbc:mysql://localhost:3306/TUTORIALS";
      String username = "root";
      String password = "password";
      try {
         Class.forName("com.mysql.cj.jdbc.Driver");
         Connection connection = DriverManager.getConnection(url, username, password);
         Statement statement = connection.createStatement();
         System.out.println("Connected successfully...!");
        //Float data types...!;
         String sql = "CREATE TABLE temp(Id INT AUTO_INCREMENT, Celsius FLOAT, Fahrenheit FLOAT, PRIMARY KEY(Id))";
         statement.execute(sql);
         System.out.println("column of a Float type created successfully...!");
         ResultSet resultSet = statement.executeQuery("DESCRIBE temp");
         while (resultSet.next()){
            System.out.println(resultSet.getString(1)+" "+resultSet.getString(2));
         }
         connection.close();
      } catch (Exception e) {
         System.out.println(e);
      }
   }
}    

输出

获得的输出如下所示 -

Connected successfully...!
column of a Float type created successfully...!
Id int
Celsius float
Fahrenheit float

import mysql.connector
# 建立连接
connection = mysql.connector.connect(
    host='localhost',
    user='root',
    password='password',
    database='tut'
)
# 创建游标对象
cursorObj = connection.cursor()
# 创建带有浮点列的表
sql = '''
CREATE TABLE datatype_demo(ID INT, 
NAME VARCHAR(50), 
HEIGHT FLOAT,
WEIGHT FLOAT
)
'''
cursorObj.execute(sql)
print("The table is created successfully!")
# Data to be inserted
data_to_insert = [
    (1, 'John', 171.3, 65.7),
    (2, 'Rob', 45, 75),
    (3, 'Salman', 12.74839, 54.262),
    (4, 'Arush', None, None),
]
# 向创建的表中插入数据
insert_query = "INSERT INTO datatype_demo (ID, NAME, HEIGHT, WEIGHT) VALUES (%s, %s, %s, %s)"
cursorObj.executemany(insert_query, data_to_insert)
# 插入操作后提交更改
connection.commit()
print("Rows inserted successfully.")
# 现在显示表记录
select_query = "SELECT * FROM datatype_demo"
cursorObj.execute(select_query)
result = cursorObj.fetchall()
print("Table Data:")
for row in result:
    print(row)
cursorObj.close()
connection.close()    

输出

以下是上述代码的输出 -

The table is created successfully!
Rows inserted successfully.
Table Data:
(1, 'John', 171.3, 65.7)
(2, 'Rob', 45.0, 75.0)
(3, 'Salman', 12.7484, 54.262)
(4, 'Arush', None, None)