---json
{
    "aliases": [
        { "path": ":docs:resource:sql_stored_function" }
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---
====== SQL Function======


===== About =====
A ''SQL'' ''Stored Function'' is a function that is 
  * stored in the database.
  * accessible by name 


A stored function may return:
  * a scalar value
  * or a result set.



===== Execution Example =====


  * [[:docs:resource:sql_select|SQL Query]] with a scalar function
```sql
select upper('lowercase to uppercase')
```
  * Upper function as stored procedure (from [[howto:postgres:procedure_with_out_parameter|this Postgres HowTo]]) with the [[:docs:system:database:jdbc_escape|JDBC escape syntax]]
```sql
{? = call upper( ? ) }"
```
  * [[:docs:resource:sql_select|SQL Query]] with the function ''setoffunc'' that returns a result set (from [[howto:postgres:function_setof|this Postgres HowTo]])
```sql
SELECT * FROM setoffunc()
```




 

===== Management =====

==== Creation ====

You create a stored function with a [[sql_dml|SQL DML Request]] that contains the SQL statements 
  * ''CREATE FUNCTION'' 
  * or ''CREATE OR REPLACE FUNCTION''

==== Execution ====


You execute a SQL ''stored function'' by:
  * using it in a [[:docs:resource:sql_select|SQL Query]].
  * by calling it as [[:docs:resource:sql_stored_procedure|SQL stored procedure]] with an ''OUT'' parameter



===== Database Support =====

The different way to call and use a function is database dependent.


The below table link to the documentation and to howtos.
Tabulify supports by default all database SQL syntax.

^ Database ^ Create Function Documentation ^ HowTo ^
| [[:howto:postgres:postgres|Postgres]] | [[https://www.postgresql.org/docs/current/sql-createfunction.htm|sql-createfunction]] | [[howto:postgres:function_setof|SETOF function]] |