SQL Server 2017

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SET LANGUAGE BRITISH;

SELECT CONVERT(date,'2018-04-03'),
       CONVERT(datetime,'2018-04-03');

(No column name)
(No column name)

2018-04-03
2018-03-04 00:00:00.000

Changed language setting to British.

SET LANGUAGE ENGLISH; --Despite this isn't English, it is America. Colour has a U in it

SELECT CONVERT(date,'2018-04-03'),
       CONVERT(datetime,'2018-04-03');

(No column name)
(No column name)

2018-04-03
2018-04-03 00:00:00.000

Changed language setting to us_english.

SET LANGUAGE BRITISH;

SELECT CONVERT(datetime,'2018-04-29');
Msg 242 Level 16 State 3 Line 3
The conversion of a varchar data type to a datetime data type resulted in an out-of-range value.