BIT is an integer type that can store the values 0 or 1.
By default, the BIT data type does not allow NULL.
A BIT value requires 1 byte of storage.
When converting a string to a BIT, leading and trailing spaces are removed. If the leading character is '+' it is ignored.
If the leading character is '-' the remaining digits are interpreted as a negative number. Leading '0' characters are skipped,
and the remaining characters are converted to an integer value. An error is returned if the value is out of the valid range
for the destination data type, if the string contains illegal characters, or if the string cannot be decoded as an integer
value.
SQL/1999
The BIT data type is SQL language feature F511 of the SQL/1999 standard.
SQL/2008
The BIT and BIT VARYING data types were dropped from the SQL/2003 standard. Hence with respect to the SQL/2008 standard,
the BIT data type is a vendor extension.