Build A Salon Appointment Scheduler

Hello,
I’m stuck. Help. Don’t know what is wrong. Help.

So I’m trying to check if the user inputs a valid service_id.
This part is not working:

    SERVICE_ID_EXISTS=$($PSQL "SELECT name FROM services WHERE service_id = $SERVICE_ID_CHOSEN")

    if [[ -z $SERVICE_ID_EXISTS ]]
    then
      MAIN_MENU "No service with the number: $SERVICE_ID_CHOSEN"
    else
      echo "test print --> $SERVICE_ID_EXISTS"
    fi

I want to check if the user types a number that corresponds to a service and if a random number is given then return to MAIN MENU with a message.

I try to implement the steps from the Build a Bike Rental Shop course. There is a part that goes like:

# get bike availability
      BIKE_AVAILABILITY=$($PSQL "SELECT available FROM bikes WHERE bike_id = $BIKE_ID_TO_RENT AND available = true")

      # if not available
      if [[ -z $BIKE_AVAILABILITY ]]
      then

        # send to main menu
        MAIN_MENU "That bike is not available."
      else

and it works fine, but in the salon script it doesn’t, because for some reason -z $SERVICE_ID_EXISTS is always false.

When I run the script I get the following results.

12

It seems like the column name and some bars from the services table (from the salon database) are saved in the $SERVICE_ID_EXISTS variable. Why is that happening?

The salon.sh so far:

#!/bin/bash
PSQL="psql --username=freecodecamp --dbname=salon -c"

echo -e "\n~~~ Welcome to The Salon ~~~\n"

MAIN_MENU() {
  if [[ $1 ]]
  then
    echo -e "\n$1"
  fi

  echo -e "\nHere are our services:"

  LIST_OF_SERVICES=$($PSQL "SELECT * FROM services")
  echo "$LIST_OF_SERVICES" | while read SERVICE_ID BAR NAME
  do
    if [[ $SERVICE_ID =~ ^[0-9]+$ ]]
    then
      echo "$SERVICE_ID) $NAME"
    fi
  done

  echo -e "\nWhat would you like to do?"
  echo -e "1) Choose a service\n2) Set an appointment\n3) Donate\n4) Leave the salon"
  read MAIN_MENU_SELECTION

  case $MAIN_MENU_SELECTION in
    1) SERVICE_MENU ;;
    2) APPOINTMENT_MENU ;;
    3) DONATION_MENU ;;
    4) EXIT ;;
    *) MAIN_MENU "Please select a valid option." ;;
  esac
}

SERVICE_MENU() {
  echo -e "\nChoose a service (type service number):"
  read SERVICE_ID_CHOSEN

  if [[ ! $SERVICE_ID_CHOSEN =~ ^[0-9]+$ ]]
  then
    MAIN_MENU "This is not a valid service number."
  else
    SERVICE_ID_EXISTS=$($PSQL "SELECT name FROM services WHERE service_id = $SERVICE_ID_CHOSEN")

    if [[ -z $SERVICE_ID_EXISTS ]]
    then
      MAIN_MENU "No service with number: $SERVICE_ID_CHOSEN"
    else
      echo "test print --> $SERVICE_ID_EXISTS"
    fi
  fi
}

APPONOINTMENT_MENU() {
  echo "Appointment Meniu"
}

DONATION_MENU() {
  echo "Donation Meniu"
}

EXIT() {
  echo "Exit Meniu"
}




MAIN_MENU

The Build a Salon Appointment Scheduler project