query.sql

SELECT
  zero.name, 
  (min(lng - offset - if(lng-offset>180, 360, 0)) + 360) % 360 + offset as min,
  max(lng - offset - if(lng-offset>=180, 360, 0)) + offset as max
FROM
   (SELECT 
      min(lng) as offset, 
      name FROM places group by name
   ) as zero
LEFT JOIN places ON (places.name = zero.name)
GROUP BY places.name
-- http://sqlfiddle.com/#!2/383a6/2

schema.sql

CREATE TABLE `places` (`name` CHAR(50), `lng` DOUBLE(10,7));
INSERT INTO `places` (`name`, `lng`)
VALUES
    ('Warszawa', 19.1),
	('Warszawa', 19.3),
	('Warszawa', 20),
	('Warszawa', 21.2),
	('Warszawa', 21.71),
	('Gironde', -1.14),
	('Gironde', -1.10),
	('Gironde', -1.0133),
	('Gironde', -0.98199),
	('Gironde', -0.85411),
	('Gironde', -0.9371),
	('Gironde', -0.7303),
	('Gironde', -0.07),
	('Gironde', 0.06067),
	('Gironde', 0.06093),
	('Gironde', 0.03419),
	('Gironde', 0.07188),
	('Gironde', 0.31034),
	('Чукотский АО', 167.98694),
	('Чукотский АО', 161.63333),
	('Чукотский АО', -179.26667),
	('Чукотский АО', 169.90298),
	('Чукотский АО', 169.90298),
	('Чукотский АО', 176.16238),
	('Чукотский АО', 166.33333),
	('Чукотский АО', 177.67938),
	('Чукотский АО', 177.67938),
	('Чукотский АО', -170.28333),
	('Чукотский АО', 167),
    ("c1", -173),("c1", +171), ("c1", +176), ("c1", +179), ("c1", -175),

    ("a1", -173),("a1", +174), ("a1", +176), ("a1", +179), ("a1", -175),
    ("a2", -93),("a2", -84), ("a2", -91),("a2", -89),
    ("a3", -5),("a3", 5),    ("a3", -3),("a3", 1),
    ("a4", 85),("a4", 95),    ("a4", 87),("a4", 91),

    ("b1", -179),("b1", -173), ("b1", -176), ("b1", -174), ("b1", -175),
    ("b2", 93),("b2", 99), ("b2", 91),("b2", 94),
    ("b3", -5),("b3", -1),    ("b3", -3),("b3", -2),
    ("b4", 87),("b4", 81),    ("b4", 86),("b4", 84),


    ("z", -87),("z", -88),("z", -89),("z", -90), ("z", -91), ("z", -92), ("z", -93),
    ("y", 87),("y", 88),("y", 89),("y", 90), ("y", 91), ("y", 92), ("y", 93),
    ("x", 150),("x", 155),("x", 160),("x", 170), ("x", 175), ("x", -175), ("x", -170)
;