在Ubuntu體系中，已經安裝了mysql，即應用sudo apt-get install mysql-server mysql-client

但是用C編譯mysql資料庫時，報錯
fatal error: mysql.h: No such file or directory
出現這個錯誤是因為體系沒有安裝mysql開發庫 

gcc -I/usr/include/mysql *.c -L/usr/lib/mysql -lmysqlclient -o *

g++ -I/usr/include/mysql csql_demo.cpp -L/usr/lib/mysql -lmysqlclient -o csql_demo.e

$ ./csql_demo.e 
Error connecting to Mysql!

change the password and the database  name and fixed it now .

    /*練習mysql資料庫的連線*/    
    #include <stdio.h>   
    #include <mysql.h>    
        
    int main()    
    {    
        MYSQL mysql;    
        int t, r;    
        /*連線之前，先用mysql_init初始化MYSQL連線控制代碼*/    
        mysql_init(&mysql);    
        /*使用mysql_real_connect連線伺服器,其引數依次為MYSQL控制代碼，伺服器IP地址，  
        登入mysql的使用者名稱，密碼，要連線的資料庫等*/    
        if(!mysql_real_connect(&mysql, "localhost", "root", "123123", "yayaya", 0, NULL, 0))     
            printf("Error connecting to Mysql!\n");    
        else    
            printf("Connected Mysql successful!\n");    
            
        /*關閉連線*/    
        mysql_close(&mysql);    
        return 0;    
    }  
 

create database yayaya;

and then do this again :

g++ -I/usr/include/mysql csql_demo.cpp -L/usr/lib/mysql -lmysqlclient -o csql_demo.e

./csql_demo.e

Connected Mysql successful!