Thread: Include a C++ variable in MySQL Query

hello, trying sql query in software, , need use user input (more precisely, input incomming network, thats half revelant)

have tried libmysqlclient , mysql++, first *close quote* + variable + *open quote* (got forum post) , seccond *close quote* << mysqlpp::quote_only << variable ); (got official doccumentation

both give me errors operator used.

here mysqlpp code right now.

sssql.cpp

code:

bool sssql::checklogin(mysqlpp::string user, mysqlpp::string pass) {     mysqlpp::string userinput = user;     mysqlpp::string passcompare = pass;     mysqlpp::connection conn(false);       if (conn.connect(database, server, user, password))     {         mysqlpp::query query = conn.query("select `password` `account` `user` = " << mysqlpp::quote_only << userinput);         mysqlpp::storequeryresult res = query.store();         if (res == userinput)         {             std::cout << "login succesfull.";         }         else         {             std::cout << "login failled.";         }      } }

sssql.h

code:

#ifndef sssql_h #define sssql_h //#include "my_global.h" // include file first avoid problems #include "mysql.h" // mysql include file #define server "localhost" #define user "root" #define password "pc" #define database "pcnviolagame" #include <stdio.h> #include <string> #include <iostream> #include <mysql++.h>  class sssql {     public:         sssql();         virtual ~sssql();          bool connectdb();         bool checklogin(mysqlpp::string, mysqlpp::string);     protected:     private: };  #endif // sssql_h

and build errors.

code:

/home/pierrick/programming/netsandbox/sssql/sssql.cpp|78|warning: "/*" within comment [-wcomment]| /home/pierrick/programming/netsandbox/sssql/sssql.cpp||in member function ‘bool sssql::checklogin(mysqlpp::string, mysqlpp::string)’:| /home/pierrick/programming/netsandbox/sssql/sssql.cpp|24|error: no match ‘operator<<’ in ‘"select `password` `account` `user` = " << (mysqlpp::quote_only_type0)0u’| /home/pierrick/programming/netsandbox/sssql/sssql.cpp|24|note: candidates are:| /usr/include/mysql++/datetime.h|217|note: std::ostream& mysqlpp::operator<<(std::ostream&, const mysqlpp::datetime&)| /usr/include/mysql++/datetime.h|217|note:   no known conversion argument 1 ‘const char [49]’ ‘std::ostream& {aka std::basic_ostream<char>&}’| /usr/include/mysql++/datetime.h|339|note: std::ostream& mysqlpp::operator<<(std::ostream&, const mysqlpp::date&)| /usr/include/mysql++/datetime.h|339|note:   no known conversion argument 1 ‘const char [49]’ ‘std::ostream& {aka std::basic_ostream<char>&}’| /usr/include/mysql++/datetime.h|456|note: std::ostream& mysqlpp::operator<<(std::ostream&, const mysqlpp::time&)| /usr/include/mysql++/datetime.h|456|note:   no known conversion argument 1 ‘const char [49]’ ‘std::ostream& {aka std::basic_ostream<char>&}’| /usr/include/mysql++/null.h|350|note: template<class type, class behavior> std::ostream& mysqlpp::operator<<(std::ostream&, const mysqlpp::null<type, behavior>&)| /usr/include/mysql++/tiny_int.h|303|note: template<class vt> std::ostream& mysqlpp::operator<<(std::ostream&, mysqlpp::tiny_int<vt>)| /usr/include/mysql++/mystring.h|657|note: std::ostream& mysqlpp::operator<<(std::ostream&, const mysqlpp::string&)| /usr/include/mysql++/mystring.h|657|note:   no known conversion argument 1 ‘const char [49]’ ‘std::ostream& {aka std::basic_ostream<char>&}’| /usr/include/mysql++/mystring.h|696|note: char mysqlpp::operator<<(mysqlpp::string, char)| /usr/include/mysql++/mystring.h|696|note:   no known conversion argument 1 ‘const char [49]’ ‘mysqlpp::string’| /usr/include/mysql++/mystring.h|696|note: char mysqlpp::operator<<(char, mysqlpp::string)| /usr/include/mysql++/mystring.h|696|note:   no known conversion argument 2 ‘mysqlpp::quote_only_type0’ ‘mysqlpp::string’| /usr/include/mysql++/mystring.h|697|note: int mysqlpp::operator<<(mysqlpp::string, int)| /usr/include/mysql++/mystring.h|697|note:   no known conversion argument 1 ‘const char [49]’ ‘mysqlpp::string’| /usr/include/mysql++/mystring.h|697|note: int mysqlpp::operator<<(int, mysqlpp::string)| /usr/include/mysql++/mystring.h|697|note:   no known conversion argument 2 ‘mysqlpp::quote_only_type0’ ‘mysqlpp::string’| /usr/include/mysql++/mystring.h|698|note: short int mysqlpp::operator<<(mysqlpp::string, short int)| /usr/include/mysql++/mystring.h|698|note:   no known conversion argument 1 ‘const char [49]’ ‘mysqlpp::string’| /usr/include/mysql++/mystring.h|698|note: short int mysqlpp::operator<<(short int, mysqlpp::string)| /usr/include/mysql++/mystring.h|698|note:   no known conversion argument 2 ‘mysqlpp::quote_only_type0’ ‘mysqlpp::string’| /usr/include/mysql++/mystring.h|699|note: long int mysqlpp::operator<<(mysqlpp::string, long int)| /usr/include/mysql++/mystring.h|699|note:   no known conversion argument 1 ‘const char [49]’ ‘mysqlpp::string’| /usr/include/mysql++/mystring.h|699|note: long int mysqlpp::operator<<(long int, mysqlpp::string)| /usr/include/mysql++/mystring.h|699|note:   no known conversion argument 2 ‘mysqlpp::quote_only_type0’ ‘mysqlpp::string’| /usr/include/mysql++/mystring.h|701|note: unsigned char mysqlpp::operator<<(mysqlpp::string, unsigned char)| /usr/include/mysql++/mystring.h|701|note:   no known conversion argument 1 ‘const char [49]’ ‘mysqlpp::string’| /usr/include/mysql++/mystring.h|701|note: unsigned char mysqlpp::operator<<(unsigned char, mysqlpp::string)| /usr/include/mysql++/mystring.h|701|note:   no known conversion argument 2 ‘mysqlpp::quote_only_type0’ ‘mysqlpp::string’| /usr/include/mysql++/mystring.h|702|note: unsigned int mysqlpp::operator<<(mysqlpp::string, unsigned int)| /usr/include/mysql++/mystring.h|702|note:   no known conversion argument 1 ‘const char [49]’ ‘mysqlpp::string’| /usr/include/mysql++/mystring.h|702|note: unsigned int mysqlpp::operator<<(unsigned int, mysqlpp::string)| /usr/include/mysql++/mystring.h|702|note:   no known conversion argument 2 ‘mysqlpp::quote_only_type0’ ‘mysqlpp::string’| /usr/include/mysql++/mystring.h|703|note: short unsigned int mysqlpp::operator<<(mysqlpp::string, short unsigned int)| /usr/include/mysql++/mystring.h|703|note:   no known conversion argument 1 ‘const char [49]’ ‘mysqlpp::string’| /usr/include/mysql++/mystring.h|703|note: short unsigned int mysqlpp::operator<<(short unsigned int, mysqlpp::string)| /usr/include/mysql++/mystring.h|703|note:   no known conversion argument 2 ‘mysqlpp::quote_only_type0’ ‘mysqlpp::string’| /usr/include/mysql++/mystring.h|704|note: long unsigned int mysqlpp::operator<<(mysqlpp::string, long unsigned int)| /usr/include/mysql++/mystring.h|704|note:   no known conversion argument 1 ‘const char [49]’ ‘mysqlpp::string’| /usr/include/mysql++/mystring.h|704|note: long unsigned int mysqlpp::operator<<(long unsigned int, mysqlpp::string)| /usr/include/mysql++/mystring.h|704|note:   no known conversion argument 2 ‘mysqlpp::quote_only_type0’ ‘mysqlpp::string’| /usr/include/mysql++/mystring.h|711|note: mysqlpp::longlong mysqlpp::operator<<(mysqlpp::string, mysqlpp::longlong)| /usr/include/mysql++/mystring.h|711|note:   no known conversion argument 1 ‘const char [49]’ ‘mysqlpp::string’| /usr/include/mysql++/mystring.h|711|note: mysqlpp::longlong mysqlpp::operator<<(mysqlpp::longlong, mysqlpp::string)| /usr/include/mysql++/mystring.h|711|note:   no known conversion argument 2 ‘mysqlpp::quote_only_type0’ ‘mysqlpp::string’| /usr/include/mysql++/mystring.h|712|note: mysqlpp::ulonglong mysqlpp::operator<<(mysqlpp::string, mysqlpp::ulonglong)| /usr/include/mysql++/mystring.h|712|note:   no known conversion argument 1 ‘const char [49]’ ‘mysqlpp::string’| ||more errors follow not being shown.| ||edit max errors limit in compiler options...| ||=== build finished: 50 errors, 1 warnings ===|

create string query , add variable strcat.
if variable number (int, float, double, etc.), convert text snprintf.

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