6lab_DONE!

Practice/27_11.sql

@@ -0,0 +1,104 @@
+-- Task 1 --
+
+CREATE OR REPLACE PROCEDURE molodec() AS $$
+DECLARE 
+    name1 varchar := 'Julia';
+    name2 varchar := 'Пустотааа';
+BEGIN
+    RAISE INFO ' %, %, вы молодцы! ', name1, name2;
+
+END $$ LANGUAGE plpgsql; 
+CALL molodec();
+
+-- Task 2 -- 
+
+CREATE OR REPLACE PROCEDURE fiiiizika() AS $$
+DECLARE
+    velocity_kmh NUMERIC := 60; 
+    time_seconds NUMERIC := 30; 
+    velocity_ms NUMERIC;
+    distance_m NUMERIC; 
+    train_length_m NUMERIC; 
+BEGIN
+
+    velocity_ms := velocity_kmh * 1000 / 3600;
+
+    distance_m := velocity_ms * time_seconds;
+    train_length_m := distance_m;
+
+    RAISE INFO ' % ', TRUNC(train_length_m);
+END;
+$$ LANGUAGE plpgsql;
+CALL fiiiizika();
+
+
+
+-- Task 3 -- 
+
+CREATE OR REPLACE PROCEDURE show_city_streets() AS $$
+DECLARE
+    city_record RECORD;
+BEGIN
+    FOR city_record IN SELECT city, street_address FROM locations
+	LOOP
+        RAISE NOTICE 'В городе % есть улица %',
+		city_record.city, city_record.street_address;
+    END LOOP;
+END;
+$$ LANGUAGE plpgsql;
+
+CALL show_city_streets();
+
+
+-- Task 4 --
+
+CREATE OR REPLACE PROCEDURE factorial(n INTEGER) AS $$
+DECLARE
+    result INTEGER := 1;
+    i INTEGER := 1;
+BEGIN
+    WHILE i <= n LOOP
+        result := result * i;
+        i := i + 1;
+    END LOOP;
+    RAISE INFO ' % ', result;
+END;
+$$ LANGUAGE plpgsql;
+
+CALL factorial(10);
+
+-- Task 5 -- 
+
+CREATE OR REPLACE FUNCTION get_employees_and_managers_names() 
+RETURNS TABLE (employee_name TEXT, manager_name TEXT) AS $$ 
+BEGIN 
+    RETURN QUERY  
+    SELECT e.first_name || ' ' || e.last_name AS employee_name,  
+           COALESCE(m.first_name || ' ' || m.last_name, 'No manager') AS manager_name 
+    FROM employees e 
+    LEFT JOIN employees m ON e.manager_id = m.employee_id; 
+END; 
+$$ LANGUAGE plpgsql;
+
+SELECT get_employees_and_managers_names();
+
+-- Task 6 -- 
+
+CREATE OR REPLACE FUNCTION binary_to_decimal(binary_num VARCHAR)
+RETURNS NUMERIC AS $$
+DECLARE
+    decimal_num NUMERIC := 0;
+    power NUMERIC := 0;
+    bit NUMERIC;
+BEGIN
+    FOR i IN REVERSE 1..LENGTH(binary_num) LOOP
+        bit := CAST(SUBSTRING(binary_num FROM i FOR 1) AS NUMERIC);
+        decimal_num := decimal_num + (bit * (2 ^ power));
+        power := power + 1;
+    END LOOP;
+    RETURN decimal_num;
+END;
+$$ LANGUAGE plpgsql;
+
+SELECT binary_to_decimal('101');
+