مساعدة : Write a PL/SQL block to print the 2nd maximum bill amount

Write a PL/SQL block to print the 2nd maximum bill amount from CUSTOMERS.
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Write a PL/SQL procedure called amount to retrieve the bill amount of the customer whose customer number will be passed as argument in this procedure. Then write a PL/SQL block to accept the customer number and print the bill amount of this customer using the amount procedure. Use appropriate exceptions in the procedure amount.
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Write a PL/SQL function called maxamt to retrieve the maximum bill amount of all customers whose customer number will be passed as argument in this function. Then write a PL/SQL block display the maximum bill amount using the maxsal function.