9.6. Bit String Functions and Operators

This section describes functions and operators for examining and manipulating bit strings, that is values of the types bit and bit varying . Aside from the usual comparison operators, the operators shown in Table 9.13 can be used. Bit string operands of & , | , and # must be of equal length. When bit shifting, the original length of the string is preserved, as shown in the examples.

The following SQL -standard functions work on bit strings as well as character strings: length , bit_length , octet_length , position , substring , overlay .

The following functions work on bit strings as well as binary strings: get_bit , set_bit . When working with a bit string, these functions number the first (leftmost) bit of the string as bit 0.

In addition, it is possible to cast integral values to and from type bit . Some examples:

44::bit(10)                    0000101100
44::bit(3)                     100
cast(-44 as bit(12))           111111010100
'1110'::bit(4)::integer        14

Note that casting to just " bit " means casting to bit(1) , and so will deliver only the least significant bit of the integer.