PostgreSQL 9.0.23 Documentation | ||||
---|---|---|---|---|

Prev | Up | Chapter 9. Functions and Operators | Next |

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
9-11 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.

Table 9-11. Bit String Operators

Operator | Description | Example | Result |
---|---|---|---|

|| |
concatenation | B'10001' || B'011' |
10001011 |

& |
bitwise AND | B'10001' & B'01101' |
00001 |

| |
bitwise OR | B'10001' | B'01101' |
11101 |

# |
bitwise XOR | B'10001' # B'01101' |
11100 |

~ |
bitwise NOT | ~ B'10001' |
01110 |

<< |
bitwise shift left | B'10001' << 3 |
01000 |

>> |
bitwise shift right | B'10001' >> 2 |
00100 |

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`

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

44::bit(10)000010110044::bit(3)100cast(-44 as bit(12))111111010100'1110'::bit(4)::integer14

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

Note:Prior to PostgreSQL 8.0, casting an integer tobit(n)would copy the leftmostnbits of the integer, whereas now it copies the rightmostnbits. Also, casting an integer to a bit string width wider than the integer itself will sign-extend on the left.

If you see anything in the documentation that is not correct, does not match your experience with the particular feature or requires further clarification, please use this form to report a documentation issue.