Hi there,
to be able to bound a drop down list to SQL data, you need to turn on the option Show Dynamic Properties within the options settings of LiveCycle Designer
Tools > Options > Data Binding > Show Dynamic Properties
Then you can select a drop down list and bind items from data connections, just click the green text in the red square in the image below :

Once in the Dynamic Properties dialog, you have all the options you need!

Data Connection: Choose the data connection to have the field's list needed
Items : If Data Connection is selected, the field is disabled
Item Text : Specify what value is suppose to be displayed to the user
Item Value : Specify what value is to be used when using the property rawValue
Hope this help!