BOOLEAN data type
The BOOLEAN data type stores TRUE or FALSE data
values as a single byte.
The following table shows internal and literal representations
of the BOOLEAN data type.
| Logical Value | Internal Representation | Literal Representation |
|---|---|---|
| TRUE | \0 | 't' |
| FALSE | \1 | 'f' |
| NULL | Internal Use Only | NULL |
You can compare two BOOLEAN values to test for equality
or inequality. You can also compare a BOOLEAN value to the Boolean
literals 't' and 'f'. BOOLEAN values
are not case-sensitive; 't' is equivalent to 'T'
and 'f' to 'F'.
You can use a BOOLEAN column to store what a Boolean expression
returns. In the following example, the value of boolean_column is
'
t' if column1 is less than column2,
'f' if column1 is greater than or equal to column2,
and NULL if the value of either column1 or column2 is
unknown: UPDATE my_table SET boolean_column = lessthan(column1, column2)