9.5. 位元字串函式及運算子

This section describes functions and operators for examining and manipulating values of typebytea.

SQLdefines some string functions that use key words, rather than commas, to separate arguments. Details are inTable 9.11.PostgreSQLalso provides versions of these functions that use the regular function invocation syntax (seeTable 9.12).

Note

The sample results shown on this page assume that the server parameterbytea_outputis set toescape(the traditional PostgreSQL format).

Table 9.11. SQLBinary String Functions and Operators

Additional binary string manipulation functions are available and are listed inTable 9.12. Some of them are used internally to implement theSQL-standard string functions listed inTable 9.11.

Table 9.12. Other Binary String Functions

get_byteandset_bytenumber the first byte of a binary string as byte 0.get_bitandset_bitnumber bits from the right within each byte; for example bit 0 is the least significant bit of the first byte, and bit 15 is the most significant bit of the second byte.

See also the aggregate functionstring_agginSection 9.20and the large object functions inSection 34.4.

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