diff --git a/week10/ex1.sql b/week10/ex1.sql
new file mode 100644
index 0000000..788b7e7
--- /dev/null
+++ b/week10/ex1.sql
@@ -0,0 +1,142 @@
+-- PART A
+CREATE TABLE accounts (id SERIAL, name VARCHAR(50), credit numeric, currency VARCHAR(10));
+INSERT INTO accounts (name, credit, currency) VALUES('Account 1', 1000, 'RUB');
+INSERT INTO accounts (name, credit, currency) VALUES('Account 2', 1000, 'RUB');
+INSERT INTO accounts (name, credit, currency) VALUES('Account 3', 1000, 'RUB');
+
+BEGIN;
+	-- T1
+	UPDATE accounts SET credit=credit-500 WHERE name='Account 1';
+	UPDATE accounts SET credit=credit+500 WHERE name='Account 3';
+	SAVEPOINT T1;
+
+	-- T2
+	UPDATE accounts SET credit=credit-700 WHERE name='Account 2';
+	UPDATE accounts SET credit=credit+700 WHERE name='Account 1';
+	SAVEPOINT T2;
+
+	-- T3
+	UPDATE accounts SET credit=credit-100 WHERE name='Account 2';
+	UPDATE accounts SET credit=credit+100 WHERE name='Account 3';
+	SAVEPOINT T3;
+
+	ROLLBACK TO T3;
+	ROLLBACK TO T2;
+	ROLLBACK TO T1;
+
+	ROLLBACK;
+
+-- PART B
+ALTER TABLE accounts ADD COLUMN BankName VARCHAR(30);
+UPDATE accounts SET BankName='SberBank' WHERE name='Account 1' OR name='Account 3';
+UPDATE accounts SET BankName='Tinkoff' WHERE name='Account 2';
+INSERT INTO accounts (name, credit, currency) VALUES('Account 4', 1000, 'RUB');
+
+BEGIN;
+	-- T1
+	UPDATE accounts SET credit=credit-500 WHERE name='Account 1';
+	UPDATE accounts SET credit=credit+500 WHERE name='Account 3';
+	DO
+	$do$
+	BEGIN
+		IF (SELECT COUNT(DISTINCT BankName) FROM accounts WHERE name='Account 1' OR name='Account 3') >= 2 THEN
+			UPDATE accounts SET credit=credit-30 WHERE name='Account 1';
+			UPDATE accounts SET credit=credit+30 WHERE name='Account 4';
+		END IF;
+	END
+	$do$;
+	SAVEPOINT T1;
+
+	-- T2
+	UPDATE accounts SET credit=credit-700 WHERE name='Account 2';
+	UPDATE accounts SET credit=credit+700 WHERE name='Account 1';
+	DO
+	$do$
+	BEGIN
+		IF (SELECT COUNT(DISTINCT BankName) FROM accounts WHERE name='Account 2' OR name='Account 1') >= 2 THEN
+			UPDATE accounts SET credit=credit-30 WHERE name='Account 2';
+			UPDATE accounts SET credit=credit+30 WHERE name='Account 4';
+		END IF;
+	END
+	$do$;
+	SAVEPOINT T2;
+
+	-- T3
+	UPDATE accounts SET credit=credit-100 WHERE name='Account 2';
+	UPDATE accounts SET credit=credit+100 WHERE name='Account 3';
+	DO
+	$do$
+	BEGIN
+		IF (SELECT COUNT(DISTINCT BankName) FROM accounts WHERE name='Account 2' OR name='Account 3') >= 2 THEN
+			UPDATE accounts SET credit=credit-30 WHERE name='Account 2';
+			UPDATE accounts SET credit=credit+30 WHERE name='Account 4';
+		END IF;
+	END
+	$do$;
+	SAVEPOINT T3;
+
+	ROLLBACK TO T3;
+	ROLLBACK TO T2;
+	ROLLBACK TO T1;
+
+	ROLLBACK;
+
+-- Part C
+CREATE TABLE Ledger (id Serial, fromId int, toId int, fee numeric, amount numeric, transactionDateTime timestamp);
+BEGIN;
+	-- T1
+	UPDATE accounts SET credit=credit-500 WHERE name='Account 1';
+	UPDATE accounts SET credit=credit+500 WHERE name='Account 3';
+	DO
+	$do$
+	BEGIN
+		IF (SELECT COUNT(DISTINCT BankName) FROM accounts WHERE name='Account 1' OR name='Account 3') >= 2 THEN
+			UPDATE accounts SET credit=credit-30 WHERE name='Account 1';
+			UPDATE accounts SET credit=credit+30 WHERE name='Account 4';
+			INSERT INTO Ledger (fromId, toId, fee, amount, transactionDateTime) Values(1, 3, 30, 500, CURRENT_TIMESTAMP);
+		ELSE
+			INSERT INTO Ledger (fromId, toId, fee, amount, transactionDateTime) Values(1, 3, 0, 500, CURRENT_TIMESTAMP);
+		END IF;
+	END
+	$do$;
+	SAVEPOINT T1;
+
+	-- T2
+	UPDATE accounts SET credit=credit-700 WHERE name='Account 2';
+	UPDATE accounts SET credit=credit+700 WHERE name='Account 1';
+	DO
+	$do$
+	BEGIN
+		IF (SELECT COUNT(DISTINCT BankName) FROM accounts WHERE name='Account 2' OR name='Account 1') >= 2 THEN
+			UPDATE accounts SET credit=credit-30 WHERE name='Account 2';
+			UPDATE accounts SET credit=credit+30 WHERE name='Account 4';
+			INSERT INTO Ledger (fromId, toId, fee, amount, transactionDateTime) Values(2, 1, 30, 700, CURRENT_TIMESTAMP);
+		ELSE
+			INSERT INTO Ledger (fromId, toId, fee, amount, transactionDateTime) Values(2, 1, 0, 700, CURRENT_TIMESTAMP);
+		END IF;
+	END
+	$do$;
+	SAVEPOINT T2;
+
+	-- T3
+	UPDATE accounts SET credit=credit-100 WHERE name='Account 2';
+	UPDATE accounts SET credit=credit+100 WHERE name='Account 3';
+	DO
+	$do$
+	BEGIN
+		IF (SELECT COUNT(DISTINCT BankName) FROM accounts WHERE name='Account 2' OR name='Account 3') >= 2 THEN
+			UPDATE accounts SET credit=credit-30 WHERE name='Account 2';
+			UPDATE accounts SET credit=credit+30 WHERE name='Account 4';
+			INSERT INTO Ledger (fromId, toId, fee, amount, transactionDateTime) Values(2, 4, 30, 100, CURRENT_TIMESTAMP);
+		ELSE
+			INSERT INTO Ledger (fromId, toId, fee, amount, transactionDateTime) Values(2, 4, 0, 100, CURRENT_TIMESTAMP);
+		END IF;
+	END
+	$do$;
+	SAVEPOINT T3;
+
+	ROLLBACK TO T3;
+	ROLLBACK TO T2;
+	ROLLBACK TO T1;
+
+	ROLLBACK;
diff --git a/week10/ex2.sql b/week10/ex2.sql
new file mode 100644
index 0000000..f595797
--- /dev/null
+++ b/week10/ex2.sql
@@ -0,0 +1,112 @@
+CREATE TABLE bank2 (id serial, username VARCHAR(50), fullname VARCHAR(50), balance numeric, Group_id int);
+INSERT INTO bank2 (username, fullname, balance, Group_id) VALUES('jones', 'Alice Jones', 82, 1);
+INSERT INTO bank2 (username, fullname, balance, Group_id) VALUES('bitdiddl', 'Ben Bitdiddle', 82, 1);
+INSERT INTO bank2 (username, fullname, balance, Group_id) VALUES('mike', 'Michael Dole', 73, 2);
+INSERT INTO bank2 (username, fullname, balance, Group_id) VALUES('alyssa', 'Alyssa P. Hacker', 79, 3);
+INSERT INTO bank2 (username, fullname, balance, Group_id) VALUES('bbrown', 'Bob Brown', 100, 3);
+
+-- Terminal 1
+BEGIN;
+SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
+SELECT * from bank2;
+--  id | username |     fullname     | balance | group_id
+-- ----+----------+------------------+---------+----------
+--   1 | jones    | Alice Jones      |      82 |        1
+--   2 | bitdiddl | Ben Bitdiddle    |      82 |        1
+--   3 | mike     | Michael Dole     |      73 |        2
+--   4 | alyssa   | Alyssa P. Hacker |      79 |        3
+--   5 | bbrown   | Bob Brown        |     100 |        3
+SELECT * from bank2;
+--  id | username |     fullname     | balance | group_id
+-- ----+----------+------------------+---------+----------
+--   1 | jones    | Alice Jones      |      82 |        1
+--   2 | bitdiddl | Ben Bitdiddle    |      82 |        1
+--   3 | mike     | Michael Dole     |      73 |        2
+--   4 | alyssa   | Alyssa P. Hacker |      79 |        3
+--   5 | bbrown   | Bob Brown        |     100 |        3
+-- Nothing changed after the change in second terminal
+
+-- Terminal 2
+BEGIN;
+SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
+UPDATE bank2 SET username='ajones' WHERE fullname='Alice Jones';
+SELECT * from bank2;
+--  id | username |     fullname     | balance | group_id
+-- ----+----------+------------------+---------+----------
+--   2 | bitdiddl | Ben Bitdiddle    |      82 |        1
+--   3 | mike     | Michael Dole     |      73 |        2
+--   4 | alyssa   | Alyssa P. Hacker |      79 |        3
+--   5 | bbrown   | Bob Brown        |     100 |        3
+--   1 | ajones   | Alice Jones      |      82 |        1
+-- The results are different because isolation level read commited allows to read only commited changes
+COMMIT;
+-- After commitment, they are the same
+
+-- Term 1
+UPDATE bank2 SET balance=balance+10 WHERE id=1;
+-- Term 2
+UPDATE bank2 SET balance=balance+20 WHERE id=1;
+-- it waits the commitment from term 1
+-- Term 1
+COMMIT;
+-- Term 2
+ROLLBACK;
+
+-- Repetable read
+UPDATE bank2 SET username='jones' WHERE fullname='Alice Jones';
+-- Term 1
+BEGIN;
+SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;
+SELECT * from bank2;
+SELECT * from bank2;
+SELECT * from bank2;
+UPDATE bank2 SET balance=balance+10 WHERE id=1;
+COMMIT;
+
+-- Term 2
+BEGIN;
+SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;
+UPDATE bank2 SET username='ajones' WHERE fullname='Alice Jones';
+COMMIT;
+BEGIN;
+SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;
+UPDATE bank2 SET balance=balance+20 WHERE id=1;
+
+-- Even after COMMIT on term 2, the data doesn't change on Term 1 because of the transaction isolation repetable read
+-- Also after the balance change on the second term this error shows up:ERROR:  could not serialize access due to concurrent update
+
+-- PART 2
+
+-- TERM 1
+BEGIN;
+SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
+SELECT * from bank2 WHERE Group_id=2;
+SELECT * from bank2 WHERE Group_id=2;
+UPDATE bank2 SET balance=balance+15 WHERE Group_id=2;
+-- Mike shows up
+
+
+-- TERM 2
+BEGIN;
+SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
+UPDATE bank2 SET Group_id=2 WHERE username='bbrown';
+
+-- BOB's balance hasn't change because when READ COMMITTED is set, it's impossible to view changes in other running transaction, so only balance of mike changed
+
+-- REPEATABLE
+UPDATE bank2 SET Group_id=3 WHERE username='bbrown';
+-- TERM 1
+BEGIN;
+SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;
+SELECT * from bank2 WHERE Group_id=2;
+SELECT * from bank2 WHERE Group_id=2;
+UPDATE bank2 SET balance=balance+15 WHERE Group_id=2;
+-- Mike shows up
+
+
+-- TERM 2
+BEGIN;
+SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;
+UPDATE bank2 SET Group_id=2 WHERE username='bbrown';
+
+-- THE same result