undefined reference to `sqlite3_exec'

This error message indicates that the linker is unable to find the implementation of the `sqlite3_exec` function.

To resolve this issue, you need to make sure that you have linked your code to the SQLite library correctly. You can do this by adding the `-lsqlite3` flag to your linker command, which tells the linker to link your code to the SQLite library.

For example, if you are using GCC, you can add the following command to link your code to the SQLite library:

gcc -o my_program my_program.c -lsqlite3

If you are using a different compiler, consult the documentation to see how to link against external libraries.