8.3. String Functions - 8.3.3. BIT_LENGTH() - 《Firebird 2.5 Language Reference》

8.3.3. BIT_LENGTH()

8.3.3. `BIT_LENGTH()`

Available in

DSQL, PSQL

Syntax

BIT_LENGTH (string)

Table 125. `BIT_LENGTH` Function Parameter
Parameter	Description
string	An expression of a string type

Result type

INTEGER

Description

Gives the length in bits of the input string. For multi-byte character sets, this may be less than the number of characters times 8 times the “formal” number of bytes per character as found in RDB$CHARACTER_SETS.

With arguments of type CHAR, this function takes the entire formal string length (i.e. the declared length of a field or variable) into account. If you want to obtain the “logical” bit length, not counting the trailing spaces, right-TRIM the argument before passing it to BIT_LENGTH.

BLOB support

Since Firebird 2.1, this function fully supports text BLOBs of any length and character set.

Examples

select bit_length('Hello!') from rdb$database
-- returns 48
select bit_length(_iso8859_1 'Grüß di!') from rdb$database
-- returns 64: ü and ß take up one byte each in ISO8859_1
select bit_length
  (cast (_iso8859_1 'Grüß di!' as varchar(24) character set utf8))
from rdb$database
-- returns 80: ü and ß take up two bytes each in UTF8
select bit_length
  (cast (_iso8859_1 'Grüß di!' as char(24) character set utf8))
from rdb$database
-- returns 208: all 24 CHAR positions count, and two of them are 16-bit