Gbase 8C string operator

GBase 8c The database provides some string operators , Use keywords instead of commas to separate parameters in these functions .

1. octet_length(string)

describe ： Number of bytes in binary string . return type ：int

Example ：

gbase=# SELECT octet_length(E'jo\\000se'::bytea) AS RESULT;

result

--------

      5

(1 row)

1. overlay(string placing string from int [for int])

describe ： Replace substring . return type ：bytea

Example ：

gbase=# SELECT overlay(E'Th\\000omas'::bytea placing E'\\002\\003'::bytea from 2 for 3) AS RESULT;

result

----------------

\x5402036d6173

(1 row)

1. position(substring in string) describe ： Location of a specific substring . return type ：int

Example ：

gbase=# SELECT position(E'\\000om'::bytea in E'Th\\000omas'::bytea) AS RESULT;

result

--------

3

(1 row)

1. substring(string [from int] [for int])

describe ： Intercept substring . return type ：bytea

Example ：

gbase=# SELECT substring(E'Th\\000omas'::bytea from 2 for 3) AS RESULT;

 result

----------

\x68006f

(1 row)

1. substr(string, from int [, for int])

describe ： Intercept substring . return type ：bytea

Example ：

gbase=# select substr(E'Th\\000omas'::bytea,2, 3) as result;

result

----------

\x68006f

(1 row)

1. trim([both] bytes from string)

describe ： from string The beginning and end of delete only contain bytes Longest string in bytes . return type ：bytea

Example ：

gbase=# SELECT trim(E'\\000'::bytea from E'\\000Tom\\000'::bytea) AS RESULT;

result

----------

\x546f6d

(1 row)