Implicit Conversion

Implicit conversion between types when the primary fields do not match may cause data truncation, the insertion of a default value, or an error message to be raised.

For example, when a datetime value is converted to a date value, the time portion is truncated, leaving only the date portion. If a time value is converted to a datetime value, a default date portion of Jan 1, 1900 is added to the new datetime value. If a date value is converted to a datetime value, a default time portion of 00:00:00:000 is added to the datetime value.

DATE -> VARCHAR, CHAR, BINARY, VARBINARY, DATETIME, SMALLDATETIME
TIME -> VARCHAR, CHAR, BINARY, VARBINARY, DATETIME, SMALLDATETIME
VARCHAR, CHAR, BINARY, VARBINARY, DATETIME, SMALLDATETIME -> DATE
VARCHAR, CHAR, BINARY, VARBINARY, DATETIME, SMALLDATETIME  -> TIME