reboot rep

3 sem/Lab#7/lab7.sql

@@ -13,36 +13,36 @@
 -- действительное число. Заполните таблицы people и people_log
 -- несколькими записями (не менее 5 на таблицу).
 
-		CREATE TABLE people (
-			id SERIAL PRIMARY KEY,
-			first_name VARCHAR(50),
-			last_name VARCHAR(50),
-			birthday DATE,
-			amount DECIMAL(10, 2)
-		);
+CREATE TABLE people (
+    id SERIAL PRIMARY KEY,
+    first_name VARCHAR(50),
+    last_name VARCHAR(50),
+    birthday DATE,
+    amount DECIMAL(10, 2)
+);
 
-		CREATE TABLE people_log (
-			id SERIAL PRIMARY KEY,
-			person_id INTEGER REFERENCES people(id),
-			operation_date TIMESTAMP,
-			sum DECIMAL(10, 2)
-		);
+CREATE TABLE people_log (
+    id SERIAL PRIMARY KEY,
+    person_id INTEGER REFERENCES people(id),
+    operation_date TIMESTAMP,
+    sum DECIMAL(10, 2)
+);
 
-		INSERT INTO people (first_name, last_name, birthday, amount) 
-		VALUES 
-		('Иван', 'Иванов', '1985-05-15', 1000.50),
-		('Петр', 'Петров', '1990-10-20', 750.25),
-		('Мария', 'Сидорова', '1978-12-03', 3000.75),
-		('Елена', 'Козлова', '1989-08-27', 200.00),
-		('Алексей', 'Смирнов', '1980-04-18', 1500.00);
+INSERT INTO people (first_name, last_name, birthday, amount) 
+VALUES 
+('Иван', 'Иванов', '1985-05-15', 1000.50),
+('Петр', 'Петров', '1990-10-20', 750.25),
+('Мария', 'Сидорова', '1978-12-03', 3000.75),
+('Елена', 'Козлова', '1989-08-27', 200.00),
+('Алексей', 'Смирнов', '1980-04-18', 1500.00);
 
-		INSERT INTO people_log (person_id, operation_date, sum) 
-		VALUES 
-		(1, '2023-09-20 10:15:00', 250.00),
-		(3, '2023-10-01 15:30:00', 800.50),
-		(2, '2023-11-05 08:45:00', 100.25),
-		(4, '2023-11-25 12:00:00', 50.00),
-		(5, '2023-12-02 18:20:00', 300.00);
+INSERT INTO people_log (person_id, operation_date, sum) 
+VALUES 
+(1, '2023-09-20 10:15:00', 250.00),
+(3, '2023-10-01 15:30:00', 800.50),
+(2, '2023-11-05 08:45:00', 100.25),
+(4, '2023-11-25 12:00:00', 50.00),
+(5, '2023-12-02 18:20:00', 300.00);
 
 SELECT * FROM people;
 SELECT * FROM people_log;
@@ -56,49 +56,47 @@ SELECT * FROM people_log;
 -- операций с отрицательной суммой и данные об общем числе операций
 -- и среднем значении суммы.
 
-CREATE OR REPLACE PROCEDURE statement_of_acount(start_date DATE, end_date DATE) AS $$ 
+CREATE OR REPLACE FUNCTION statement_of_account(start_date DATE, end_date DATE) RETURNS VOID AS $$
 DECLARE  
-    pos_sum RECORD;
-    neg_sum RECORD;
-    total_count INTEGER;
-    avg_amount NUMERIC;
-	const CONSTANT INTEGER = 3;
-	
+    pos_counter INTEGER := 0;
+    neg_counter INTEGER := 0;
+    total_sum NUMERIC := 0;
+    total_count INTEGER := 0;
+    const CONSTANT INTEGER := 3;
+    avg_amount NUMERIC := 0;
+    operation RECORD;
 BEGIN
-    FOR pos_sum IN (
+    FOR operation IN (
         SELECT operation_date, sum
         FROM people_log
-        WHERE operation_date BETWEEN start_date AND end_date AND sum > 0
-        ORDER BY sum DESC
-        LIMIT const
+        WHERE operation_date BETWEEN start_date AND end_date
+        ORDER BY sum
     ) LOOP
-        RAISE INFO 'Positive: %, Sum: %', pos_sum.operation_date, pos_sum.sum;
+        IF operation.sum > 0 THEN
+            pos_counter := pos_counter + 1;
+            IF pos_counter <= const THEN
+                RAISE INFO 'Positive: %, Sum: %', operation.operation_date, operation.sum;
+            END IF;
+        ELSE
+            neg_counter := neg_counter + 1;
+            IF neg_counter <= const THEN
+                RAISE INFO 'Negative: %, Sum: %', operation.operation_date, operation.sum;
+            END IF;
+        END IF;
+        
+        total_sum := total_sum + operation.sum;
+        total_count := total_count + 1;
     END LOOP;
 
-    FOR neg_sum IN (
-        SELECT operation_date, sum
-        FROM people_log
-        WHERE operation_date BETWEEN start_date AND end_date AND sum < 0
-        ORDER BY sum ASC
-        LIMIT const
-    ) LOOP
-        RAISE INFO 'Negative: %, Sum: %', neg_sum.operation_date, neg_sum.sum;
-    END LOOP;
-
-    SELECT COUNT(*) INTO total_count
-    FROM people_log
-    WHERE operation_date BETWEEN start_date AND end_date;
-
-    SELECT AVG(sum) INTO avg_amount
-    FROM people_log
-    WHERE operation_date BETWEEN start_date AND end_date;
+    IF total_count > 0 THEN
+        avg_amount := total_sum / total_count;
+    END IF;
     
     RAISE INFO 'Total number of operations: %', total_count;
     RAISE INFO 'Average amount of transactions: %', avg_amount;
+END
+$$ LANGUAGE plpgsql;
 
-END $$ LANGUAGE plpgsql; 
-
-CALL statement_of_acount('2023-01-01', '2023-12-31');
 
 
 -- Задание 3
@@ -115,14 +113,62 @@ CALL statement_of_acount('2023-01-01', '2023-12-31');
 
 CREATE OR REPLACE PROCEDURE account_operation(new_id integer, add_sum numeric) AS $$ 
 DECLARE
+m integer;
 BEGIN 
+select into m count(operation_date) from people_log where to_char(operation_date,'DD')= to_char(now(),'DD');
+if m>=3 then
+
     UPDATE people 
 	SET amount = amount + add_sum 
 	WHERE id = new_id;
     INSERT INTO people_log (person_id, operation_date, sum) VALUES (new_id, CURRENT_TIMESTAMP(0), add_sum);
+ELSE
+raise info 'Too many operations'
 END $$ LANGUAGE plpgsql; 
 
 CALL account_operation(5, 1000000);
 
 SELECT * FROM people;
 SELECT * FROM people_log;
+
+
+CREATE OR REPLACE FUNCTION statement_of_account(start_date DATE, end_date DATE) RETURNS VOID AS $$
+DECLARE  
+    pos_counter INTEGER := 0;
+    neg_counter INTEGER := 0;
+    total_sum NUMERIC := 0;
+    total_count INTEGER := 0;
+    const CONSTANT INTEGER := 3;
+    avg_amount NUMERIC := 0;
+    operation RECORD;
+BEGIN
+    FOR operation IN (
+        SELECT operation_date, sum
+        FROM people_log
+        WHERE operation_date BETWEEN start_date AND end_date
+        ORDER BY sum
+    ) LOOP
+        IF operation.sum > 0 THEN
+            pos_counter := pos_counter + 1;
+            IF pos_counter <= const THEN
+                RAISE INFO 'Positive: %, Sum: %', operation.operation_date, operation.sum;
+            END IF;
+        ELSE
+            neg_counter := neg_counter + 1;
+            IF neg_counter <= const THEN
+                RAISE INFO 'Negative: %, Sum: %', operation.operation_date, operation.sum;
+            END IF;
+        END IF;
+        
+        total_sum := total_sum + operation.sum;
+        total_count := total_count + 1;
+    END LOOP;
+
+    IF total_count > 0 THEN
+        avg_amount := total_sum / total_count;
+    END IF;
+    
+    RAISE INFO 'Total number of operations: %', total_count;
+    RAISE INFO 'Average amount of transactions: %', avg_amount;
+END
+$$ LANGUAGE plpgsql;

3 sem/Lab/Lab#6/bd6_inserts.sql

@@ -0,0 +1,47 @@
+DROP TABLE IF EXISTS bd6_departments;
+DROP TABLE IF EXISTS bd6_employees;
+
+
+CREATE TABLE bd6_departments(
+  id integer PRIMARY KEY,
+  name varchar(64),
+  postal_code varchar(6),
+  street varchar(64),
+  building varchar(16),
+  city varchar(32)
+);
+
+INSERT INTO bd6_departments 
+VALUES(10, 'Administration', '109658', 'Leningradskoe shosse', '1', 'Moscow'),
+(20, 'Marketing', '107701', 'Lenina', '22a', 'Volgograd'),
+(30, 'Purchasing', '109901', 'Mikluho-Maklaya', '8', 'Bryansk'),
+(40, 'Human Resources', '10967', '5-ya parkovaya', '16', 'Moscow'),
+(50, 'Shipping', '109659', '38 Bakinskih komissarov', '77', 'Moscow'),
+(60, 'IT', '109902', 'Pervomajskaya', '33', 'Kirov');
+
+CREATE TABLE bd6_employees(
+  id integer PRIMARY KEY,
+  last_name varchar(64) NOT NULL,
+  first_name varchar(64) NOT NULL,
+  phone_number varchar(18),
+  email varchar(32),
+  department_id integer NOT NULL,
+  manager_id integer,
+  salary_in_euro numeric(8, 2)  DEFAULT 0 NOT NULL,
+  UNIQUE(last_name, first_name, department_id)
+);
+
+
+INSERT INTO bd6_employees VALUES(1, 'Radygin', 'Victor', '8-(495)-567-7788', 'vr@e.mail.mephi.ru', 10, NULL, 8000),
+(2, 'Kuprijanov', 'Dmitrij', '8-(495)-567-7794', 'kd@e.mail.mephi.ru', 60, 1, 6534.33),
+(3, 'Ivanov-Skladovskij', 'Ivan', '8-(495)-567-7799', 'ii1@mail.mephi.ru', 20, 1, 4404.14),
+(4, 'Petrov', 'Petr', '8-(495)-567-7794', 'petrovpetr@m.gmail.ru', 60, 2, 3456.43),
+(5, 'kozlov', 'Konstantin', '8-(495)-567-7794', 'kkozlov@mephi.ru', 60, 2, 2300),
+(6, 'Abramov', 'Abram', '8-(495)-567-7794', 'abramova@k75.mephi.ru', 60, 2, 2200.11),
+(7, 'IvanovпїЅ-SkladovskпїЅya-Petrova', 'Ivanka', '8-(495)-567-7794', 'ii2@mail.mephi.ru', 60, 4, 3756.33),
+(8, 'Petrov', 'Ivan', '8-(495)-567-7799', 'petrovivan@m.gmail.ru', 20, 3, 4850),
+(9, 'kozlov', 'Ivan', '8-(495)-567-7799', 'ikozlov@mephi.ru', 20, 3, 3460),
+(10, 'Abramov', 'Moisej', '8-(495)-567-7794', 'abramovm@k75.mephi.ru', 60, 4, 2345),
+(11, 'Petrov', 'Alex', '8-(495)-567-7799', 'petroval@m.gmail.ru', 20, 3, 2465),
+(12, 'kozlov', 'Maxim', '8-(495)-567-7799', 'mkozlov@mephi.ru', 20, 3, 2788),
+(13, 'Abramov', 'Isyaslav', '8-(495)-567-7738', 'abramovi@k75.mephi.ru', 30, 1, 6500);

3 sem/Lab/Lab#6/insert.sql

@@ -1,13 +1,13 @@
 DROP TABLE IF EXISTS bd6_employees;
 
--- CREATE TABLE bd6_departments(
---   id integer PRIMARY KEY,
---   name varchar(64),
---   postal_code varchar(6),
---   street varchar(64),
---   building varchar(16),
---   city varchar(32)
--- );
+CREATE TABLE bd6_departments(
+  id integer PRIMARY KEY,
+  name varchar(64),
+  postal_code varchar(6),
+  street varchar(64),
+  building varchar(16),
+  city varchar(32)
+);
 CREATE TABLE
     bd6_employees (
         id integer PRIMARY KEY,
@@ -21,13 +21,13 @@ CREATE TABLE
         UNIQUE (last_name, first_name, department_id)
     );
 
--- INSERT INTO bd6_departments 
--- VALUES(10, 'Administration', '109658', 'Leningradskoe shosse', '1', 'Moscow'),
--- (20, 'Marketing', '107701', 'Lenina', '22a', 'Volgograd'),
--- (30, 'Purchasing', '109901', 'Mikluho-Maklaya', '8', 'Bryansk'),
--- (40, 'Human Resources', '10967', '5-ya parkovaya', '16', 'Moscow'),
--- (50, 'Shipping', '109659', '38 Bakinskih komissarov', '77', 'Moscow'),
--- (60, 'IT', '109902', 'Pervomajskaya', '33', 'Kirov');
+INSERT INTO bd6_departments 
+VALUES(10, 'Administration', '109658', 'Leningradskoe shosse', '1', 'Moscow'),
+(20, 'Marketing', '107701', 'Lenina', '22a', 'Volgograd'),
+(30, 'Purchasing', '109901', 'Mikluho-Maklaya', '8', 'Bryansk'),
+(40, 'Human Resources', '10967', '5-ya parkovaya', '16', 'Moscow'),
+(50, 'Shipping', '109659', '38 Bakinskih komissarov', '77', 'Moscow'),
+(60, 'IT', '109902', 'Pervomajskaya', '33', 'Kirov');
 INSERT INTO
     bd6_employees
 VALUES

3 sem/Lab/Lab#6/lab6_done.sql

@@ -189,6 +189,33 @@ call f();
 
 -- Task 7 from lab4 -- 
 
+
+CREATE table staff(
+	id integer primary key,
+	name varchar(64) NOT NULL,
+	department varchar(64) NOT NULL
+);
+
+CREATE SEQUENCE staff_id_seq
+	START WITH 12
+	CYCLE
+	INCREMENT BY 8
+	CACHE 100;
+	
+
+INSERT INTO staff VALUES
+	(nextval('staff_id_seq'), 'Ivan Makarenko', 'Director');
+	
+INSERT INTO staff
+	(SELECT nextval('staff_id_seq'), last_name, department_name
+	 FROM employees e JOIN departments d ON e.department_id = d.department_id);
+	 
+UPDATE staff SET department = 'Innovations department'
+	WHERE id < 40;
+	
+DELETE FROM staff 
+	WHERE name ILIKE('%K%');
+
 CREATE VIEW dep_staff_counts AS
 SELECT department, COUNT(*) AS ecount
 FROM staff
@@ -200,42 +227,224 @@ SELECT * FROM dep_staff_counts;
 
 
 
-CREATE OR REPLACE PROCEDURE department_names(integer) AS $$
+-- CREATE OR REPLACE PROCEDURE department_names(integer) AS $$
+-- DECLARE 
+-- 	d_attrs RECORD;
+-- 	i INTEGER;
+-- 	l INTEGER;
+-- BEGIN
+-- FOR d_attrs IN 
+-- 	(
+-- 	SELECT id,last_name, first_name, manager_id
+-- 	FROM bd6_employees order by manager_id 
+-- 	)   
+-- 	LOOP
+-- 		IF d_attrs.manager_id=$1 THEN
+--     		RAISE INFO ' % % % % ', d_attrs.first_name, d_attrs.last_name, d_attrs.id, d_attrs.manager_id;    
+-- 			l:= d_attrs.id;
+--     	CALL department_names(l);    
+-- 	END IF;
+-- END LOOP; 
+-- END $$ LANGUAGE plpgsql; 
+
+
+-- CREATE OR REPLACE PROCEDURE department_names2(integer) AS $$
+-- DECLARE d_attrs RECORD;
+-- BEGIN
+-- 	FOR d_attrs IN 
+-- 	(
+-- 	SELECT id,last_name, first_name, manager_id   
+-- 	FROM bd6_employees 
+-- 	order by manager_id 
+-- 	)
+      
+-- LOOP   
+-- 	if d_attrs.id=$1 then    
+-- 	RAISE INFO ' % % % % ', d_attrs.first_name, d_attrs.last_name, d_attrs.id, d_attrs.manager_id;
+-- 	end if;
+-- 	END LOOP; 
+-- CALL department_names($1);
+-- END $$ LANGUAGE plpgsql; 
+-- CALL department_names2(4);
+
+
+/* Вариант 1 || Работа 6 || Антипенко, Дробышевский */
+
+
+-- Task 1 -- 
+-- Пункт а)
+WITH RECURSIVE tmp AS (
+
+  SELECT id, first_name, last_name, manager_id, 1 AS level
+  FROM bd6_employees
+  WHERE id = 1
+  UNION all
+  SELECT e.id, e.first_name, e.last_name, e.manager_id, t.level + 1
+  FROM bd6_employees e
+  JOIN tmp t ON e.manager_id = t.id 
+)
+SELECT * 
+FROM tmp
+;
+
+-- Пункт б)
+CREATE OR REPLACE PROCEDURE depa(integer) AS $$
 DECLARE 
 	d_attrs RECORD;
-	i INTEGER;
-	l INTEGER;
+	i integer;
+	l integer;
 BEGIN
 FOR d_attrs IN 
 	(
 	SELECT id,last_name, first_name, manager_id
-	FROM bd6_employees order by manager_id 
+	FROM bd6_employees 
+	ORDER BY manager_id
 	)   
 	LOOP
-		IF d_attrs.manager_id=$1 THEN
-    		RAISE INFO ' % % % % ', d_attrs.first_name, d_attrs.last_name, d_attrs.id, d_attrs.manager_id;    
-			l:= d_attrs.id;
-    	CALL department_names(l);    
+	IF d_attrs.manager_id=$1 THEN
+	 	RAISE INFO ' % % % % ', d_attrs.first_name, d_attrs.last_name, d_attrs.id, d_attrs.manager_id;   
+		l:= d_attrs.id;
+    	CALL depa(l); 
 	END IF;
-END LOOP; 
+	END LOOP; 
 END $$ LANGUAGE plpgsql; 
 
-
-CREATE OR REPLACE PROCEDURE department_names2(integer) AS $$
-DECLARE d_attrs RECORD;
-BEGIN
+CREATE OR REPLACE PROCEDURE dep(integer) AS $$
+DECLARE
+	d_attrs RECORD;
+	BEGIN
 	FOR d_attrs IN 
 	(
-	SELECT id,last_name, first_name, manager_id   
+	SELECT 
+		id,
+		last_name, 
+		first_name, 
+		manager_id   
 	FROM bd6_employees 
-	order by manager_id 
+	ORDER BY manager_id
 	)
       
-LOOP   
-	if d_attrs.id=$1 then    
+	LOOP   
+	IF d_attrs.id=$1 THEN   
 	RAISE INFO ' % % % % ', d_attrs.first_name, d_attrs.last_name, d_attrs.id, d_attrs.manager_id;
-	end if;
+    END IF;
 	END LOOP; 
-CALL department_names($1);
+CALL depa($1);
 END $$ LANGUAGE plpgsql; 
-CALL department_names2(4);
+CALL dep(1);   
+
+-- Task 2 --
+
+UPDATE bd6_employees SET salary_in_euro = 299 WHERE id = 3;
+
+CREATE OR REPLACE PROCEDURE print_employees() AS $$
+DECLARE
+current_salary INTEGER;
+m_salary INTEGER;
+mod_salary INTEGER := 0;
+employee_rec RECORD;
+i INTEGER = 0;
+cnt INTEGER;
+BEGIN
+SELECT COUNT(*) INTO cnt FROM bd6_employees;
+FOR employee_rec IN 
+	(
+   SELECT last_name, first_name, salary_in_euro 
+   FROM bd6_employees 
+   ORDER BY salary_in_euro
+	) 
+LOOP
+
+	current_salary := employee_rec.salary_in_euro;
+	
+	IF cnt - 1 = i THEN 
+	m_salary := ((current_salary) / 100) * 100 + mod_salary;
+	ELSE 
+	m_salary := ((current_salary) / 100) * 100;
+	END IF;
+
+RAISE NOTICE 'Employee: % % || Modified Salary: %', employee_rec.last_name, employee_rec.first_name, m_salary;
+
+mod_salary := mod_salary + mod(current_salary, 100);
+i := i+1;
+
+END LOOP;
+
+END $$ LANGUAGE plpgsql;
+
+CALL print_employees();
+SELECT * 
+FROM bd6_employees
+ORDER BY salary_in_euro;
+
+
+-- Task 3 -- 
+CREATE OR REPLACE FUNCTION rearrange_salaries() RETURNS VOID AS $$
+DECLARE
+    salaries RECORD;
+	small NUMERIC[];
+	larg NUMERIC[];
+	const CONSTANT INTEGER = 10;
+BEGIN
+    FOR salaries IN 
+        SELECT id, salary_in_euro
+        FROM bd6_employees 
+        ORDER BY salary_in_euro 
+        LIMIT const
+	LOOP
+		small = array_append(small, (SELECT salary_in_euro FROM bd6_employees WHERE id = salaries.id));
+		UPDATE bd6_employees SET manager_id = NULL WHERE manager_id = salaries.id;
+    	DELETE FROM bd6_employees
+    	WHERE id = salaries.id;
+	END LOOP;
+
+    FOR salaries IN 
+        SELECT id, salary_in_euro
+        FROM bd6_employees 
+        ORDER BY salary_in_euro DESC 
+        LIMIT const
+	LOOP
+		larg = array_append(larg, (SELECT id FROM bd6_employees WHERE id = salaries.id));
+	END LOOP;
+	
+	FOR i IN 1..const
+	LOOP
+        UPDATE bd6_employees
+        SET salary_in_euro = salary_in_euro + small[i]
+        WHERE id = larg[i];
+    END LOOP;
+END;
+$$ LANGUAGE plpgsql;
+SELECT rearrange_salaries();
+
+-- Task 4 --
+
+CREATE OR REPLACE PROCEDURE f() AS $$ 
+DECLARE d_attrs RECORD; 
+BEGIN
+
+FOR d_attrs IN WITH RECURSIVE tmp AS ( 
+    SELECT 1+i*5 AS f1, 2+i*5 AS f2, 3+i*5 AS f3, 4+i*5 AS f4,5+i*5 AS f5 
+    FROM generate_series(0,199) i)
+
+SELECT * FROM tmp 
+LOOP 
+case 
+when ( mod(d_attrs.f1,2)!=0) 
+then RAISE INFO ' % % % % %', d_attrs.f1, d_attrs.f2, d_attrs.f3, d_attrs.f4, d_attrs.f5; 
+when ( mod(d_attrs.f1,2)=0) 
+then RAISE INFO ' % % % % %', d_attrs.f5, d_attrs.f4, d_attrs.f3, d_attrs.f2, d_attrs.f1; 
+end case; 
+END LOOP; 
+END $$ LANGUAGE plpgsql; 
+call f();
+
+-- Task 7 from lab4 -- 
+DROP VIEW IF EXISTS dep_staff_counts;
+
+CREATE VIEW dep_staff_counts AS
+SELECT department, COUNT(*) AS ecount
+FROM staff
+GROUP BY department;
+
+SELECT * FROM dep_staff_counts;

task 1.sql

@@ -0,0 +1,72 @@
+--2
+SELECT *
+FROM bd_departments
+WHERE LENGTH(street) = POWER(SQRT(75 + LENGTH(street)), 2) / 4;
+
+INSERT INTO bd_departments VALUES
+(35,'meow', 407596, 'aaaaaaaaaaaaaaaaaaaaaaaaa', 2, 'MSK');
+--4
+CREATE TABLE employees_backup AS
+SELECT *, 
+    CASE 
+        WHEN random() < 0.5 THEN 'Active'
+        ELSE 'Inactive'
+    END AS employee_status
+FROM bd_employees;
+SELECT * FROM employees_backup;
+--5
+SELECT e.employee_id, e.first_name, e.last_name, e.manager_id
+FROM employees e
+JOIN employees m ON e.manager_id = m.employee_id
+WHERE LENGTH(m.last_name) > 6;
+
+--3--
+
+DO $$
+DECLARE
+BEGIN
+    RAISE NOTICE 'Шахматная доска:';
+    CALL chess('z9', 'C');
+ 
+
+    RAISE NOTICE 'Размещение фигуры А на клетке A5:';
+    CALL chess('a5', ' A ');
+
+
+    RAISE NOTICE 'Размещение фигуры У на клетке H4:';
+    CALL chess('h4', ' Y ');
+
+
+END $$;
+
+
+
+CREATE OR REPLACE PROCEDURE chess(pos varchar, bukva char) AS $$
+DECLARE
+    board text;
+    queen_col integer;
+    queen_row integer;
+BEGIN
+    queen_col := ascii(substring(pos from 1 for 1)) - 96;
+    queen_row := substring(pos from 2)::integer;
+	
+    FOR i IN 1..8 LOOP
+        board := '';
+		
+        FOR j IN 1..8 LOOP
+            IF i = queen_row AND j = queen_col THEN
+                board := board || bukva;
+            ELSE
+                IF (i + j) % 2 = 0 THEN
+                    board := board || ' б ';
+                ELSE
+                    board := board || ' ч ';
+                END IF;
+            END IF;
+        END LOOP;
+		
+        RAISE NOTICE '%', board;
+    END LOOP;
+END
+$$ LANGUAGE plpgsql;
+SELECT chess('c3');

task3.sql

@@ -0,0 +1,32 @@
+DO $$
+DECLARE
+    board CHAR(8)[][] := ARRAY[
+        ARRAY['б', 'ч', 'б', 'ч', 'б', 'ч', 'б', 'ч'],
+        ARRAY['ч', 'б', 'ч', 'б', 'ч', 'б', 'ч', 'б'],
+        ARRAY['б', 'ч', 'б', 'ч', 'б', 'ч', 'б', 'ч'],
+        ARRAY['ч', 'б', 'ч', 'б', 'ч', 'б', 'ч', 'б'],
+        ARRAY['б', 'ч', 'б', 'ч', 'б', 'ч', 'б', 'ч'],
+        ARRAY['ч', 'б', 'ч', 'б', 'ч', 'б', 'ч', 'б'],
+        ARRAY['б', 'ч', 'б', 'ч', 'б', 'ч', 'б', 'ч'],
+        ARRAY['ч', 'б', 'ч', 'б', 'ч', 'б', 'ч', 'б']
+    ];
+
+BEGIN
+    RAISE NOTICE 'Шахматная доска:';
+    FOR i IN REVERSE 1..8 LOOP
+        RAISE NOTICE '%', board[i];
+    END LOOP;
+
+    RAISE NOTICE 'Размещение фигуры А на клетке A5:';
+    board[8 - 5 + 1][ASCII('A') - 64] := 'A';
+    FOR i IN REVERSE 1..8 LOOP
+        RAISE NOTICE '%', board[i];
+    END LOOP;
+
+    RAISE NOTICE 'Размещение фигуры У на клетке H4:';
+    board[8 - ч + 1][ASCII('H') - 64] := 'У';
+    FOR i IN REVERSE 1..8 LOOP
+        RAISE NOTICE '%', board[i];
+    END LOOP;
+
+END $$;