CREATE TABLE employees (
id int primary key,
name varchar(24),
department varchar(24),
salary int,
employ_id int);

INSERT INTO employees VALUES 
(1001, 'Ivanov', 'SAPIENS', 100000, 1001),
(1002, 'Petrov', 'SAPIENS', 100000, 1001),
(1003, 'Sidorov', 'TECHNOLOGIES', 130000, 1001),
(1004, 'Korotkov', 'TECHNOLOGIES', 120000, 1001),
(1005, 'Filev', 'SAPIENS', 90000, 1001),
(1006, 'Smirnov', 'REVOLT', 125000, 1001),
(1007, 'Godov', 'REVOLT', 125000, 1001);

CREATE TABLE business_trip (
id int primary key,
employ_id int,
dep_date DATE,
arriv_date DATE,
trav_expens int);

INSERT INTO business_trip
VALUES
(2001, 1001, '2014-01-01', '2014-01-10', 2000),
(2002, 1001, '2015-01-01', '2015-01-10', 3000),
(2003, 1001, '2015-02-01', '2015-03-10', 1500),
(2004, 1001, '2015-06-01', '2015-07-10', 2900),
(2005, 1001, '2015-07-01', '2015-08-10', 3600),
(2006, 1001, '2016-01-01', '2016-01-10', 5000),
(2007, 1001, '2016-04-01', '2016-06-10', 2000),
(2008, 1001, '2016-07-01', '2016-08-10', 5700),
(2009, 1001, '2017-01-01', '2017-01-10', 2100),
(2010, 1001, '2017-03-01', '2017-04-10', 5000); 

SELECT SUM(b.trav_expens) AS SUM_TRAV_EXPENS
FROM employees AS e LEFT JOIN business_trip AS b
ON e.employ_id = b.employ_id
WHERE e.salary > 90000 AND b.dep_date >= '2015-06-01';