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Forum Update on Monday, May 27th 2025

Connect to MYSQL failed in Qt

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qt6c++mysqlmysql server
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  • SGaistS Offline
    SGaistS Offline
    SGaist
    Lifetime Qt Champion
    wrote on last edited by
    #9

    The SQL module is supported in Qt 6. However the MySQL plugin might not be provided because Oracle changed their licensing.

    As for your build issue: -L is for giving path to search, it's -l for stating the name of the library.

    Interested in AI ? www.idiap.ch
    Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

    1 Reply Last reply
    1
    • Christian EhrlicherC Offline
      Christian EhrlicherC Offline
      Christian Ehrlicher
      Lifetime Qt Champion
      wrote on last edited by
      #10

      So the QtSql module has no errors - please stay specific!

      else:unix: LIBS += -L$$PWD/lib/libmysql.lib

      This is for sure not correct.

      Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
      Visit the Qt Academy at https://academy.qt.io/catalog

      E 2 Replies Last reply
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      • Christian EhrlicherC Christian Ehrlicher

        So the QtSql module has no errors - please stay specific!

        else:unix: LIBS += -L$$PWD/lib/libmysql.lib

        This is for sure not correct.

        E Offline
        E Offline
        ELEMENTICY
        wrote on last edited by ELEMENTICY
        #11

        @Christian-Ehrlicher but qtsql mysql plugin doesnt provided as @SGaist said it,i tried add it by following youtube tutorial,it still doesnt.Lemme try it again and send the error here

        1 Reply Last reply
        0
        • Christian EhrlicherC Christian Ehrlicher

          So the QtSql module has no errors - please stay specific!

          else:unix: LIBS += -L$$PWD/lib/libmysql.lib

          This is for sure not correct.

          E Offline
          E Offline
          ELEMENTICY
          wrote on last edited by
          #12

          @Christian-Ehrlicher

          This is for sure not correct.

          oh,how do i fix it?

          SGaistS 1 Reply Last reply
          0
          • E ELEMENTICY

            @Christian-Ehrlicher

            This is for sure not correct.

            oh,how do i fix it?

            SGaistS Offline
            SGaistS Offline
            SGaist
            Lifetime Qt Champion
            wrote on last edited by
            #13

            @ELEMENTICY said in Connect to MYSQL failed in Qt:

            @Christian-Ehrlicher

            This is for sure not correct.

            oh,how do i fix it?

            Re-read my previous answer.

            Interested in AI ? www.idiap.ch
            Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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            • SGaistS SGaist

              @ELEMENTICY said in Connect to MYSQL failed in Qt:

              @Christian-Ehrlicher

              This is for sure not correct.

              oh,how do i fix it?

              Re-read my previous answer.

              E Offline
              E Offline
              ELEMENTICY
              wrote on last edited by
              #14

              @SGaist so i have to make it

              win32:CONFIG(release, debug|release): LIBS += -L$$PWD/lib/ -l libmysql
              else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/lib/ -l libmysqld
              else:unix: LIBS += -L$$PWD/lib/ -l libmysql
              

              ?

              1 Reply Last reply
              0
              • SGaistS Offline
                SGaistS Offline
                SGaist
                Lifetime Qt Champion
                wrote on last edited by
                #15

                No space no "lib" prefix.

                It's explained in the documentation

                Interested in AI ? www.idiap.ch
                Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                • SGaistS SGaist

                  No space no "lib" prefix.

                  It's explained in the documentation

                  E Offline
                  E Offline
                  ELEMENTICY
                  wrote on last edited by
                  #16

                  @SGaist my current profile code:

                  win32:CONFIG(release, debug|release): LIBS += -L$$PWD/lib/ -llibmysql
                  else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/lib/ -llibmysqld
                  else:unix: LIBS += -L$$PWD/lib/ -llibmysql
                  

                  documentation:

                  LIBS += -L"3rdparty/CatWhisperer/lib" -lCatWhisperer
                  

                  i got this error:
                  :-1: error: error: cannot find -llibmysql

                  proof that path exists:
                  Screenshot 2021-05-07 191143.png

                  SGaistS 1 Reply Last reply
                  0
                  • E ELEMENTICY

                    @Christian-Ehrlicher i do,

                    win32:CONFIG(release, debug|release): LIBS += -L$$PWD/lib/libmysql
                    else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/lib/libmysqld
                    else:unix: LIBS += -L$$PWD/lib/libmysql
                    

                    And yea,use qt sql it just give like 11 error
                    And if i use official mysql mysql.h,it only give 2 error which is undefine

                    And yea,or i need to change my profile's lib code to this?

                    win32:CONFIG(release, debug|release): LIBS += -L$$PWD/lib/libmysql.lib
                    else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/lib/libmysqld.lib
                    else:unix: LIBS += -L$$PWD/lib/libmysql.lib
                    
                    Christian EhrlicherC Offline
                    Christian EhrlicherC Offline
                    Christian Ehrlicher
                    Lifetime Qt Champion
                    wrote on last edited by
                    #17

                    @ELEMENTICY said in Connect to MYSQL failed in Qt:

                    And yea,use qt sql it just give like 11 error

                    What does this mean?

                    Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                    Visit the Qt Academy at https://academy.qt.io/catalog

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                    • E ELEMENTICY

                      @SGaist my current profile code:

                      win32:CONFIG(release, debug|release): LIBS += -L$$PWD/lib/ -llibmysql
                      else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/lib/ -llibmysqld
                      else:unix: LIBS += -L$$PWD/lib/ -llibmysql
                      

                      documentation:

                      LIBS += -L"3rdparty/CatWhisperer/lib" -lCatWhisperer
                      

                      i got this error:
                      :-1: error: error: cannot find -llibmysql

                      proof that path exists:
                      Screenshot 2021-05-07 191143.png

                      SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #18

                      @ELEMENTICY did you read what I wrote ? No "lib" prefix.

                      Interested in AI ? www.idiap.ch
                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                      E 2 Replies Last reply
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                      • SGaistS SGaist

                        @ELEMENTICY did you read what I wrote ? No "lib" prefix.

                        E Offline
                        E Offline
                        ELEMENTICY
                        wrote on last edited by
                        #19

                        @SGaist
                        current code:

                        win32:CONFIG(release, debug|release): LIBS += -L$$PWD/lib/libmysql
                        else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/lib/libmysqld
                        else:unix: LIBS += -L$$PWD/lib/libmysql
                        

                        idk if i misunderstanded what u mean,but it still give error ;/
                        or u mean i have to remove that -L

                        SGaistS 1 Reply Last reply
                        0
                        • SGaistS SGaist

                          @ELEMENTICY did you read what I wrote ? No "lib" prefix.

                          E Offline
                          E Offline
                          ELEMENTICY
                          wrote on last edited by
                          #20

                          @SGaist and yea i dont know if its because im working on a android app,so it doesnt work

                          SGaistS 1 Reply Last reply
                          0
                          • E ELEMENTICY

                            @SGaist
                            current code:

                            win32:CONFIG(release, debug|release): LIBS += -L$$PWD/lib/libmysql
                            else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/lib/libmysqld
                            else:unix: LIBS += -L$$PWD/lib/libmysql
                            

                            idk if i misunderstanded what u mean,but it still give error ;/
                            or u mean i have to remove that -L

                            SGaistS Offline
                            SGaistS Offline
                            SGaist
                            Lifetime Qt Champion
                            wrote on last edited by
                            #21

                            @ELEMENTICY said in Connect to MYSQL failed in Qt:

                            @SGaist
                            current code:

                            win32:CONFIG(release, debug|release): LIBS += -L$$PWD/lib/libmysql
                            else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/lib/libmysqld
                            else:unix: LIBS += -L$$PWD/lib/libmysql
                            

                            idk if i misunderstanded what u mean,but it still give error ;/
                            or u mean i have to remove that -L

                            You have to understand what -L and -l each do. I have already explained that before. So please re-read the corresponding answers.

                            Interested in AI ? www.idiap.ch
                            Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                            • E ELEMENTICY

                              @SGaist and yea i dont know if its because im working on a android app,so it doesnt work

                              SGaistS Offline
                              SGaistS Offline
                              SGaist
                              Lifetime Qt Champion
                              wrote on last edited by
                              #22

                              @ELEMENTICY said in Connect to MYSQL failed in Qt:

                              @SGaist and yea i dont know if its because im working on a android app,so it doesnt work

                              Oracle does not provide pre-built binaries for Android.

                              Interested in AI ? www.idiap.ch
                              Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                              • E Offline
                                E Offline
                                ELEMENTICY
                                wrote on last edited by ELEMENTICY
                                #23

                                @SGaist dude,im so tired...
                                Can you pleaseee write the 3 lines of code for me?
                                Please... i hope after you see this message,you wont just ignore and think i never hard work on it..But im tired for just add a simple library already...
                                It will be the BEST help for me

                                My current code...

                                win32:CONFIG(release, debug|release): LIBS += $$PWD/lib/ -llibmysql
                                else:win32:CONFIG(debug, debug|release): LIBS += $$PWD/lib/ -llibmysqld
                                else:unix: LIBS += $$PWD/lib/ -llibmysql
                                

                                Error:
                                :-1: error: error: cannot open C:/Users/ELEMENT/Documents/PosSystem/Pos/lib/: Permission denied
                                I opened QT Creator with Administrator,still same...

                                I also tried..

                                win32:CONFIG(release, debug|release): LIBS += $$PWD/lib/libmysql
                                else:win32:CONFIG(debug, debug|release): LIBS += $$PWD/lib/libmysqld
                                else:unix: LIBS += $$PWD/lib/libmysql
                                

                                Error:
                                :-1: error: no such file or directory: 'C:/Users/ELEMENT/Documents/PosSystem/Pos/lib/libmysql' clang++: error: no such file or directory: 'C:/Users/ELEMENT/Documents/PosSystem/Pos/lib/libmysql' make: *** [Makefile:79: libPos_x86_64.so] Error 1
                                Seems like that one is the wrong way to do without adding -l

                                appreciate it...

                                1 Reply Last reply
                                0
                                • E Offline
                                  E Offline
                                  ELEMENTICY
                                  wrote on last edited by
                                  #24

                                  @SGaist I removed:

                                  win32:CONFIG(release, debug|release): LIBS += $$PWD/lib/ -llibmysql
                                  else:win32:CONFIG(debug, debug|release): LIBS += $$PWD/lib/ -llibmysqld
                                  else:unix: LIBS += $$PWD/lib/ -llibmysql
                                  

                                  And tried only

                                  LIBS += -L"lib" -llibmysql
                                  

                                  Still error:
                                  :-1: error: error: cannot find -llibmysql

                                  1 Reply Last reply
                                  0
                                  • SGaistS Offline
                                    SGaistS Offline
                                    SGaist
                                    Lifetime Qt Champion
                                    wrote on last edited by
                                    #25

                                    "Drop the lib prefix": -lmysql

                                    To repeat myself: Oracle does not provide pre-built binaries for Android.

                                    Also, @Christian-Ehrlicher already asked you several times: what exact error did you get with the QtSql module ?

                                    Interested in AI ? www.idiap.ch
                                    Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                                    E 1 Reply Last reply
                                    1
                                    • SGaistS SGaist

                                      "Drop the lib prefix": -lmysql

                                      To repeat myself: Oracle does not provide pre-built binaries for Android.

                                      Also, @Christian-Ehrlicher already asked you several times: what exact error did you get with the QtSql module ?

                                      E Offline
                                      E Offline
                                      ELEMENTICY
                                      wrote on last edited by ELEMENTICY
                                      #26

                                      @SGaist ok its weird,it now dont give any error.But its EXCELENT!
                                      But it unable to connect to Server
                                      My code:

                                      QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
                                              db.setHostName("localhost");
                                              db.setDatabaseName("pos");
                                              db.setUserName("root");
                                      
                                              if (!db.open()){
                                                  ui->error->setText("Oops,Unable to connect to Server!Please contact your Administrator for help.");
                                              }
                                      

                                      Includes:

                                      #include <QtSql/QSql>
                                      #include <QtSql/QSqlDatabase>
                                      #include <QtSql/QSqlDriver>
                                      #include <QtSql/QSqlQuery>
                                      

                                      and i also added sql to Qt in Profile

                                      QT       += core gui sql
                                      
                                      E 1 Reply Last reply
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                                      • E ELEMENTICY

                                        @SGaist ok its weird,it now dont give any error.But its EXCELENT!
                                        But it unable to connect to Server
                                        My code:

                                        QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
                                                db.setHostName("localhost");
                                                db.setDatabaseName("pos");
                                                db.setUserName("root");
                                        
                                                if (!db.open()){
                                                    ui->error->setText("Oops,Unable to connect to Server!Please contact your Administrator for help.");
                                                }
                                        

                                        Includes:

                                        #include <QtSql/QSql>
                                        #include <QtSql/QSqlDatabase>
                                        #include <QtSql/QSqlDriver>
                                        #include <QtSql/QSqlQuery>
                                        

                                        and i also added sql to Qt in Profile

                                        QT       += core gui sql
                                        
                                        E Offline
                                        E Offline
                                        ELEMENTICY
                                        wrote on last edited by
                                        #27

                                        @ELEMENTICY im sure i entered correct server info

                                        JonBJ 1 Reply Last reply
                                        0
                                        • E ELEMENTICY

                                          @ELEMENTICY im sure i entered correct server info

                                          JonBJ Online
                                          JonBJ Online
                                          JonB
                                          wrote on last edited by JonB
                                          #28

                                          @ELEMENTICY
                                          So your root user has no password to connect to MySQL?

                                          If db.open() fails, why don't you print out db.lastError() into your error message?

                                          E 1 Reply Last reply
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