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How to Make A Function In Oracle?

6 minutes read

To create a function in Oracle, you can use the CREATE FUNCTION statement followed by the function name and parameters. Inside the function body, you can write the logic that performs the desired operation and returns a value. Functions can be used to encapsulate reusable code and simplify complex calculations or data manipulations. Make sure to define the return type of the function using the RETURN keyword. Once the function is created, you can call it like any other built-in function in Oracle SQL statements or PL/SQL blocks.


How to make a function in Oracle that generates a unique alphanumeric code?

Here is a sample function in Oracle that generates a unique alphanumeric code:

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CREATE OR REPLACE FUNCTION generate_code 
RETURN VARCHAR2 
IS
    v_code VARCHAR2(10);
BEGIN
    v_code := DBMS_RANDOM.STRING('X', 8);
    
    INSERT INTO unique_codes (code)
    SELECT v_code
    FROM dual
    WHERE NOT EXISTS (
        SELECT 1
        FROM unique_codes
        WHERE code = v_code
    );
    
    RETURN v_code;
END;
/


In this function, we use the DBMS_RANDOM.STRING function to generate a random alphanumeric string of length 8. We then insert this generated code into a table unique_codes only if it does not already exist in the table. Finally, we return the generated code.


Note: You may need to modify the function to suit your specific requirements, such as the length of the generated code or the table structure where the unique codes will be stored.


How to make a function in Oracle that converts a number to a string?

To create a function in Oracle that converts a number to a string, you can use the TO_CHAR function. Here is an example of how you can define a function named number_to_string that takes a number as input and returns a string representation of that number:

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CREATE OR REPLACE FUNCTION number_to_string (p_number IN NUMBER)
RETURN VARCHAR2
IS
    v_string VARCHAR2(100); -- Adjust the size based on your requirements
BEGIN
    SELECT TO_CHAR(p_number)
    INTO v_string
    FROM DUAL;
    
    RETURN v_string;
END;
/


You can then call this function in your SQL queries to convert a number to a string:

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SELECT number_to_string(123) AS num_string
FROM DUAL;


This will return the string '123'. Feel free to adjust the function and the data types/sizes based on your specific requirements.


How to make a function in Oracle that calculates the sum of all prime numbers up to a given number?

To create a function in Oracle that calculates the sum of all prime numbers up to a given number, you can follow these steps:

  1. Create a function using PL/SQL that takes a single input parameter, which is the maximum number up to which you want to calculate the sum of prime numbers.
  2. Inside the function, write a loop that iterates through numbers starting from 2 (since 2 is the first prime number) up to the input parameter.
  3. Within the loop, check if the current number is a prime number. You can do this by writing a separate function that checks if a number is prime or not.
  4. If the current number is prime, add it to a running total sum variable.
  5. Finally, return the sum of all prime numbers up to the given input number.


Here is an example of how the function can be implemented:

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CREATE OR REPLACE FUNCTION sum_prime_numbers(num IN NUMBER)
RETURN NUMBER IS
    total_sum NUMBER := 0;
    
    FUNCTION is_prime(n IN NUMBER) RETURN BOOLEAN IS
        i NUMBER := 2;
    BEGIN
        IF n < 2 THEN
            RETURN FALSE;
        END IF;
        
        WHILE i <= SQRT(n) LOOP
            IF MOD(n, i) = 0 THEN
                RETURN FALSE;
            END IF;
            
            i := i + 1;
        END LOOP;
        
        RETURN TRUE;
    END is_prime;
BEGIN
    FOR i IN 2..num LOOP
        IF is_prime(i) THEN
            total_sum := total_sum + i;
        END IF;
    END LOOP;
    
    RETURN total_sum;
END sum_prime_numbers;
/


You can then call this function with the maximum number you want to calculate the sum of prime numbers up to, like this:

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SELECT sum_prime_numbers(10) FROM dual;


This will return the sum of all prime numbers up to 10.


How to make a function in Oracle that counts the number of vowels in a string?

You can create a function in Oracle that counts the number of vowels in a given string by following these steps:

  1. Create a new function using the CREATE FUNCTION statement:
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CREATE OR REPLACE FUNCTION count_vowels(input_string IN VARCHAR2) RETURN NUMBER IS


  1. Declare a variable to store the count of vowels:
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vowel_count NUMBER := 0;


  1. Use a FOR loop to iterate through each character in the input string and check if it is a vowel (A, E, I, O, U, a, e, i, o, u):
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BEGIN
    FOR i IN 1..LENGTH(input_string) LOOP
        IF UPPER(SUBSTR(input_string, i, 1)) IN ('A', 'E', 'I', 'O', 'U') THEN
            vowel_count := vowel_count + 1;
        END IF;
    END LOOP;
    RETURN vowel_count;
END;


  1. End the function definition using the END keyword.


Here is the complete code for the function to count the number of vowels in a string:

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CREATE OR REPLACE FUNCTION count_vowels(input_string IN VARCHAR2) RETURN NUMBER IS
    vowel_count NUMBER := 0;
BEGIN
    FOR i IN 1..LENGTH(input_string) LOOP
        IF UPPER(SUBSTR(input_string, i, 1)) IN ('A', 'E', 'I', 'O', 'U') THEN
            vowel_count := vowel_count + 1;
        END IF;
    END LOOP;
    RETURN vowel_count;
END;


You can call this function with a string as an argument to count the number of vowels in that string. For example:

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SELECT count_vowels('Hello World') FROM DUAL;


This will return the number of vowels in the string "Hello World".


How to make a function in Oracle that checks if a string contains only alphabetic characters?

You can create a PL/SQL function in Oracle that checks if a string contains only alphabetic characters by using regular expressions. Here is an example implementation:

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CREATE OR REPLACE FUNCTION is_alpha(input_string IN VARCHAR2) RETURN BOOLEAN IS
  v_pattern VARCHAR2(100) := '^[[:alpha:]]+$';
BEGIN
  IF REGEXP_LIKE(input_string, v_pattern) THEN
    RETURN TRUE;
  ELSE
    RETURN FALSE;
  END IF;
END;
/


You can then use this function to check if a string contains only alphabetic characters like this:

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SELECT is_alpha('abc') FROM DUAL; -- Returns TRUE
SELECT is_alpha('abc123') FROM DUAL; -- Returns FALSE


This function uses a regular expression pattern ^[[:alpha:]]+$ which matches a string that contains only alphabetic characters. The REGEXP_LIKE function is used to check if the input string matches the pattern. If it does, the function returns TRUE, otherwise it returns FALSE.


How to make a function in Oracle that returns the current date?

To create a function in Oracle that returns the current date, you can use the following code:

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CREATE OR REPLACE FUNCTION get_current_date
RETURN DATE
IS
    current_date DATE;
BEGIN
    SELECT SYSDATE INTO current_date FROM dual;
    
    RETURN current_date;
END;
/


You can then call the function get_current_date to get the current date:

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SELECT get_current_date() FROM dual;


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