I have created a function, now i want to use that function in my query. I have two in parameters to pass in the function. How can i use that query in my function
Related
I have 4 queries with MIN(), MAX(), AVG(), stddev_pop() functions. But I need a way in which I can generalize these queries into a single query with structure
"param1(param2)".
where param1 can be MIN/MAX/AVG/stddev_pop. And param 2 can be the argument to these functions.
But I am not able to do so.
create a wrapper
function void(function_name, listparam, numberparam)
split params as the number is mentioned (ex:max 1 param)
inside use select case when function='selectedfunction' than call function with splitted params.
I'm trying to select data using below sql and created the following function to split the data but I get SQL0440n error.
The error "SQL0440n" simply means that a function (aka routine) in your SQL statement has not been found.
SQL0440N No authorized routine named "<routine-name>" of type
"<routine-type>" having compatible arguments was found.
If it is a user defined function, you will need to qualify it with a schema name when you use it, or alter your CURRENT PATH to let Db2 find the function by looking in a given set of schemas.
https://www.ibm.com/support/knowledgecenter/en/SSEPGG_11.5.0/com.ibm.db2.luw.sql.ref.doc/doc/r0001014.html
If you still get the same error, check that the data-types of the input values to the function match, or are implicitly castable to the data-types in your function parameters
Is it possible using JPA to have a custom aggregation function that would extend concat() so that it concatenates a column values into a single string?
I faced the same problem recently with JPA and H2 database. I tried to call the GROUP_CONCAT function from JPQL with a function invocation (see below) with no success. Finally, I used a native query call instead.
However, the JPA 2.1 specifications mention that you can call (function invocation) a predefined or user-defined database function either scalar or aggregate one. I have reproduced thereafter the paragraph from the specfication by highlighting the relevant part.
4.6.17.3 Invocation of Predefined and User-defined Database Functions
The invocation of functions other than the built-in functions of the Java Persistence query language is supported by means of the function_invocation syntax. This includes the invocation of predefined database functions and user-defined database functions.
function_invocation::= FUNCTION(function_name {, function_arg}*)
function_arg ::=
literal |
state_valued_path_expression |
input_parameter |
scalar_expression
The function_name argument is a string that denotes the database function that is to be invoked. The arguments must be suitable for the database function that is to be invoked. The result of the function must be suitable for the invocation context.
The function may be a database-defined function or a user-defined function. The function may be a scalar function or an aggregate function.
Applications that use the function_invocation syntax will not be portable across databases.
Example:
SELECT c
FROM Customer c
WHERE FUNCTION(‘hasGoodCredit’, c.balance, c.creditLimit)
Reference: Java Persistence 2.1, Final Release
I want to create a function in pgsql that will take three parameters and return a single value (1 row, 1 col).
I have the query working but can not seem to find a proper example of creating a function to do this.
Take a look at the example on this page, or this one.
If you actually go through the documentation there are multiple example of various functions and return types.
I am writing a PL/pgSQL function. The function has input parameters which specify (indirectly), which tables to read filtering information from.
The function embeds business logic which allows it to select data from different tables based on the input arguments. The function dynamically builds a subquery which returns filtering data which is then used to run the main query.
My questions are:
Is it 'legal' to use a dynamic subquery in a PL/pgSQL function. I cant see why not - but this question is related to the next one.
AFAIK, PL/pgSQL are cached or precompiled by the query engine. How does having a function that generates dynamic subqueries impact the work of the query engine?
"38.5.4. Executing Dynamic Commands"