You need to install the unixodbc-dev
package to get the development header files.
sudo apt-get install unixodbc-dev
The -dev
packages contain the require header files required to compile and build programs using these headers to make calls to the library. The library files themselves would be part of the regular package i.e. unixodbc
in your case.
If you want to know which package provides a certain file, you could use apt-file
:
sudo apt-file update
sudo apt-file find sql.h