Tip If you have pattern matching needs that go beyond this, consider writing a user-defined function in Perl or Tcl. The following example illustrates creating and calling a standalone function. Aside from the basic does this string match this pattern operators, functions are available to extract or replace matching substrings and to split a string at matching locations. For backward compatibility, the name can be enclosed by single quotes. Here, we use this option for PostgreSQL, it Can be SQL, C, internal, or the name of a user-defined procedural language.
Plpgsql is the name of the language that the function is implemented in. The operator ->returns JSON object field by text. The operator ->returns JSON object field by key. The AS keyword is used for creating a standalone function. PostgreSQL provides two native operators ->and ->to help you query JSON data. The return_datatype can be a base, composite, or domain type, or can reference the type of a table column.įunction-body contains the executable part. RETURN clause specifies that data type you are going to return from the function. The function must contain a return statement. option allows modifying an existing function. PostgreSQL REPLACE function Sometimes, you want to search and replace a string in a column with a new one such as replacing outdated phone numbers, broken URLs, and spelling mistakes. Replaces all occurrences in string of substring from with substring to.
RETURNS return_datatype AS $variable_name$įunction-name specifies the name of the function. replace ( string text, from text, to text) text. The basic syntax to create a function is as follows −ĬREATE FUNCTION function_name (arguments) Functions allow database reuse as other applications can interact directly with your stored procedures instead of a middle-tier or duplicating code.įunctions can be created in a language of your choice like SQL, PL/pgSQL, C, Python, etc. PostgreSQL functions, also known as Stored Procedures, allow you to carry out operations that would normally take several queries and round trips in a single function within the database.
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