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Are there any string functions in PostgreSQL SQL?
Some functions also exist natively for the bit-string types. SQL defines some string functions that use key words, rather than commas, to separate arguments. Details are in Table 9-6 . PostgreSQL also provides versions of these functions that use the regular function invocation syntax (see Table 9-7 ).
How to return NULL in string function in PostgreSQL?
Coerce the given value to text and then quote it as a literal; or, if the argument is null, return NULL. Embedded single-quotes and backslashes are properly doubled. Return all captured substrings resulting from matching a POSIX regular expression against the string.
How is a string formatted in PostgreSQL?
Concatenates all but the first argument, with separators. The first argument is used as the separator string, and should not be NULL. Other NULL arguments are ignored. Formats arguments according to a format string; see Section 9.4.1. This function is similar to the C function sprintf.
How to cast string to text in PostgreSQL?
If you want to concatenate an array’s text equivalent, cast it to text explicitly.) Checks whether the string is in the specified Unicode normalization form. The optional form key word specifies the form: NFC (the default), NFD, NFKC, or NFKD.
Some functions also exist natively for the bit-string types. SQL defines some string functions that use key words, rather than commas, to separate arguments. Details are in Table 9-8. PostgreSQL also provides versions of these functions that use the regular function invocation syntax (see Table 9-9 ).
What is name of output column in PostgreSQL?
The name of an output column in the RETURNS TABLE syntax. This is effectively another way of declaring a named OUT parameter, except that RETURNS TABLE also implies RETURNS SETOF. The data type of an output column in the RETURNS TABLE syntax. The name of the language that the function is implemented in.
When to use create or replace function in PostgreSQL?
When CREATE OR REPLACE FUNCTION is used to replace an existing function, the ownership and permissions of the function do not change. All other function properties are assigned the values specified or implied in the command. You must own the function to replace it (this includes being a member of the owning role).
How to format a string in PostgreSQL 9.6?
Supported formats are: base64, hex, escape. escape converts zero bytes and high-bit-set bytes to octal sequences ( nn) and doubles backslashes. format(formatstr text [, formatarg “any” [.] ]) Format arguments according to a format string. This function is similar to the C function sprintf. See Section 9.4.1.