Learn PLSQL with Real Code Examples

DECLARE
    count NUMBER := 0;
    isDark BOOLEAN := FALSE;
BEGIN
    -- Display initial state
    DBMS_OUTPUT.PUT_LINE('Counter: ' || count);
    DBMS_OUTPUT.PUT_LINE('Theme: ' || CASE WHEN isDark THEN 'Dark' ELSE 'Light' END);

    -- Increment counter
    count := count + 1;
    DBMS_OUTPUT.PUT_LINE('Counter: ' || count);

    -- Toggle theme
    isDark := NOT isDark;
    DBMS_OUTPUT.PUT_LINE('Theme: ' || CASE WHEN isDark THEN 'Dark' ELSE 'Light' END);

    -- Decrement counter
    count := count - 1;
    DBMS_OUTPUT.PUT_LINE('Counter: ' || count);

    -- Reset counter
    count := 0;
    DBMS_OUTPUT.PUT_LINE('Counter: ' || count);
END;

Demonstrates a simple counter with theme toggling using PL/SQL variables and DBMS_OUTPUT for output.

DECLARE
    a NUMBER := 10;
    b NUMBER := 20;
    sum NUMBER;
BEGIN
    sum := a + b;
    DBMS_OUTPUT.PUT_LINE('Sum: ' || sum);
END;

Adds two numbers and prints the result.

DECLARE
    fact NUMBER := 1;
    i NUMBER;
BEGIN
    FOR i IN 1..5 LOOP
        fact := fact * i;
    END LOOP;
    DBMS_OUTPUT.PUT_LINE('Factorial: ' || fact);
END;

Calculates factorial of 5 using a loop.

DECLARE
    fib1 NUMBER := 0;
    fib2 NUMBER := 1;
    next NUMBER;
BEGIN
    DBMS_OUTPUT.PUT_LINE(fib1);
    DBMS_OUTPUT.PUT_LINE(fib2);
    FOR i IN 3..10 LOOP
        next := fib1 + fib2;
        DBMS_OUTPUT.PUT_LINE(next);
        fib1 := fib2;
        fib2 := next;
    END LOOP;
END;

Generates first 10 Fibonacci numbers.

DECLARE
    a NUMBER := 15;
    b NUMBER := 25;
    max_val NUMBER;
BEGIN
    IF a > b THEN
        max_val := a;
    ELSE
        max_val := b;
    END IF;
    DBMS_OUTPUT.PUT_LINE('Max: ' || max_val);
END;

Finds the maximum of two numbers.

DECLARE
    type num_array IS TABLE OF NUMBER INDEX BY PLS_INTEGER;
    nums num_array;
    sum NUMBER := 0;
BEGIN
    nums(1) := 1; nums(2) := 2; nums(3) := 3; nums(4) := 4; nums(5) := 5;
    FOR i IN 1..5 LOOP
        sum := sum + nums(i);
    END LOOP;
    DBMS_OUTPUT.PUT_LINE('Sum: ' || sum);
END;

Sums elements of an array.

DECLARE
    type num_array IS TABLE OF NUMBER INDEX BY PLS_INTEGER;
    nums num_array;
BEGIN
    nums(1) := 1; nums(2) := 2; nums(3) := 3; nums(4) := 4; nums(5) := 5;
    FOR i IN 1..5 LOOP
        IF MOD(nums(i), 2) = 0 THEN
        DBMS_OUTPUT.PUT_LINE('Even: ' || nums(i));
        END IF;
    END LOOP;
END;

Prints even numbers from a given array.

DECLARE
    count NUMBER := 3;
BEGIN
    IF count < 5 THEN
        count := count + 1;
    END IF;
    DBMS_OUTPUT.PUT_LINE('Count: ' || count);
END;

Increment counter only if it is less than 5.

DECLARE
    count NUMBER := 0;
BEGIN
    -- Increment 3 times
    count := count + 1;
    count := count + 1;
    count := count + 1;
    DBMS_OUTPUT.PUT_LINE('Count: ' || count);
    -- Reset
    count := 0;
    DBMS_OUTPUT.PUT_LINE('Count after reset: ' || count);
END;

Counter that increments and can be reset to zero.

DECLARE
    isDark BOOLEAN := FALSE;
BEGIN
    DBMS_OUTPUT.PUT_LINE('Theme: ' || CASE WHEN isDark THEN 'Dark' ELSE 'Light' END);
    isDark := NOT isDark;
    DBMS_OUTPUT.PUT_LINE('Theme: ' || CASE WHEN isDark THEN 'Dark' ELSE 'Light' END);
    isDark := NOT isDark;
    DBMS_OUTPUT.PUT_LINE('Theme: ' || CASE WHEN isDark THEN 'Dark' ELSE 'Light' END);
END;

Toggles theme state multiple times.