I am trying to use temp table in user defined function for DB2. I am trying to do this in data studio but the code below is not working. How can I make this work?
Thanks.
CREATE FUNCTION BELSIZE.TEST (aSTRING VARCHAR(50))
RETURNS TABLE(
column1 INTEGER
)
F1: BEGIN ATOMIC
DECLARE c1 CURSOR WITH RETURN TO CLIENT FOR stmt;
SET v_dynStmt = 'SELECT 1 column1 from sysibm.sysdummy1';
PREPARE stmt FROM v_dynStmt;
OPEN c1;
RETURN
END
You have syntax errors in your code, more details below.
Apart from syntax errors, your title mentions temp table but your code does not, so your question is poor.
Never write "...is not working", instead write the exact SQLCODE and SQLSTATE and message that you see.
When asking for help with Db2, always write in the question the Db2-version and the operating-system (Z/OS, i-Series, Linux/Unix/Windows) on which the Db2-server runs, because the answer can depend on those facts. Different versions of Db2 for different operating systems have different capabilities and different syntax.
If you want to use cursors for result-sets then use SQL PL stored-procedures, because there are fewer restrictions.
SQL table functions are suitable when you don't need to declare a cursor for result-set.
Db2-LUW prevents you from declaring a cursor in an SQL table function when you use BEGIN ATOMIC.
If you are not using BEGIN ATOMIC, Db2-LUW (current versions, i.e. v11.1) lets you declare a cursor in an SQL UDF but you cannot use that cursor directly to return the result-set, as you can do inside SQL PL stored procedures.
For your example, the syntax below is valid and also useless, so consider using an SQL PL procedure instead:
--#SET TERMINATOR #
CREATE or replace FUNCTION BELSIZE.TEST (aSTRING VARCHAR(50))
RETURNS TABLE( column1 INTEGER)
language sql
specific belsize.test
BEGIN atomic
RETURN select 1 as column1 from sysibm.sysdummy1 ;
END
#
select * from table(belsize.test('a')) as t
#
Related
CREATE PROCEDURE A()
LANGUAGE SQL
RESULT SETS 1
BEGIN
DECLARE C1 CURSOR WITH RETURN FOR
SELECT id, name, dept, job FROM staff;
OPEN C1;
END
CREATE PROCEDURE B()
LANGUAGE SQL
BEGIN
Call a ;
END
In programming, they don't use stored procedure for returning value (they use function). Why does DB2 support that way?
In my above case, how does the stored procedure B know c1 cursor from stored procedure A? If I declare a cursor (c2 cursor) in stored procedure B and send to stored procedure A. Stored procedure A has a parameter (OUT c2 cursor), so why must I write 'RESULT SETS 1' (Can't I omit that phrase), because I don't return any cursor from stored procedure A (I return by parameter).
You might benefit from some education and training about SQL PL.
If you prefer a paper book, get "Db2 SQL Procedural Language for Linux, Unix, and Windows" by Paul Yip, Drew Bradstock and others. ISBN 0-13-100772-6.
Stackoverflow is not a substitute for training and education.
You should ask separate questions for different topics.
Research Db2 'table functions' to learn how to return a table from a function.
Research Db2 'strongly typed cursors', and Db2 'weakly typed cursors' and pipelined functions, to learn how to exploit cursor parameters in routines. Understand the many restrictions and rules associated with these things, which cannot be conveyed by one example in one question. In particular, realise that SQL PL cursor parameters can only be fully manipulated by SQL PL and cannot currently be passed to other languages for processing (except jdbc which has support for consuming such cursors). So if your front end client is using C, C++, Python, Javascript, .Net, PHP etc, then you won't use SQL PL cursor parameters currently. You might use them inside Db2 SQL PL code however, depending on your skills and needs.
To consume a result set from a nested stored procedure, you need extra syntax. When returning a result-set from a stored-procedure the dynamic result sets clause is required when defining the procedure. Returning a result set in this manner is understood by many different programming languages and frameworks, and by other RDBMS tools, so is the most general purpose method for returning data from an RDBMS to a 3rd Generation programming language. Other mechanisms can be built based on this technique.
All of this syntax is documented in the Db2 Knowledge Centre for your version and platform. One example cannot convey all possible syntax.
Here is an example, you will find many others online if you are competent with search.
--#SET TERMINATOR #
CREATE or replace PROCEDURE procA()
LANGUAGE SQL
RESULT SETS 1
BEGIN
DECLARE C1 CURSOR WITH RETURN TO CALLER FOR
SELECT id, name, dept, job FROM staff;
OPEN C1;
END
#
set serveroutput on#
CREATE or replace PROCEDURE B()
LANGUAGE SQL
BEGIN
declare sqlstate char(5) default '00000';
declare v_rs result_set_locator varying;
declare v_id smallint;
declare v_dept smallint;
declare v_name varchar(9);
declare v_job char(5);
Call procA() ;
associate result set locator (v_rs) with procedure procA;
allocate v_rscur cursor for result set v_rs;
fetch from v_rscur into v_id, v_name, v_dept, v_job;
while ( sqlstate = '00000') do
-- do something with the values just fetched...
-- i.e. process the data in the current row of the result-set
call dbms_output.put_line('id:'||varchar(v_id)||' name: '||v_name||' dept: '||varchar(v_dept)||' job: '||v_job);
-- in this example just write the data to the output stream
fetch from v_rscur into v_id, v_name, v_dept, v_job;
end while;
return;
END
#
I am attempting to get a better understanding of the DO command in postgreSQL 9.1
I have following code block,
DO
$do$
BEGIN
IF 1=1 THEN
SELECT 'foo';
ELSE
SELECT 'bar';
END IF;
END
$do$
However it returns the following error:
[42601] ERROR: query has no destination for result data Hint: If you want to discard the results of a SELECT, use PERFORM instead. Where: PL/pgSQL function "inline_code_block" line 4 at SQL statement
PostgreSQL DO command creates and executes some specific short life function. This function has not any interface, and then it cannot to return any output other then changes data in tables and some debug output.
Your example has more than one issues:
Only PostgreSQL table functions can returns some tabular data. But the mechanism is significantly different than MSSQL. PostgreSQL user's should to use RETURN NEXT or RETURN QUERY commands.
CREATE OR REPLACE FUNCTION foo(a int)
RETURNS TABLE(b int, c int) AS $$
BEGIN
RETURN QUERY SELECT i, i + 1 FROM generate_series(1,a) g(i);
END;
$$ LANGUAGE plpgsql;
SELECT * FROM foo(10);
DO anonymous functions are not table functions - so no output is allowed.
PostgreSQL 9.1 is not supported version, please upgrade
If you have some experience only from MSSQL, then forget it. A concept of stored procedures of PostgreSQL is very similar to Oracle or DB2, and it is significantly different to MSSQL does. T-SQL integrates procedural and SQL constructs to one set. Oracle, PostgreSQL, ... procedural functionality can embedded SQL, but procedural functionality is not integrated to SQL.
Please, read PostgreSQL PLpgSQL documentation for better imagine about this technology.
I have a stored procedure that performs inserts and updates in the tables. The need to create it was to try to centralize all the scan functions before inserting or updating records. Today the need arose to return the value of the field ID of the table so that my application can locate the registry and perform other stored procedures.
Stored procedure
SET TERM ^ ;
CREATE OR ALTER procedure sp_insupd (
iaction varchar(3),
iusuario varchar(20),
iip varchar(15),
imodulo varchar(30),
ifieldsvalues varchar(2000),
iwhere varchar(1000),
idesclogs varchar(200))
returns (
oid integer)
as
declare variable vdesc varchar(10000);
begin
if (iaction = 'ins') then
begin
vdesc = idesclogs;
/*** the error is on the line below ***/
execute statement 'insert into '||:imodulo||' '||:ifieldsvalues||' returning ID into '||:oid||';';
end else
if (iaction = 'upd') then
begin
execute statement 'select '||:idesclogs||' from '||:imodulo||' where '||:iwhere into :vdesc;
execute statement 'execute procedure SP_CREATE_AUDIT('''||:imodulo||''');';
execute statement 'update '||:imodulo||' set '||:ifieldsvalues||' where '||:iwhere||';';
end
insert into LOGS(USUARIO, IP, MODULO, TIPO, DESCRICAO) values (
:iusuario, :iip, :imodulo, (case :iaction when 'ins' then 1 when 'upd' then 2 end), :vdesc);
end^
SET TERM ; ^
The error in the above line is occurring due to syntax error. The procedure is compiled normally, that is, the error does not happen in the compilation, since the line in question is executed through the "execute statement". When there was no need to return the value of the ID field, the procedure worked normally with the line like this:
...
execute statement 'insert into '||:imodulo||' '||:ifieldsvalues||';';
...
What would be the correct way for the value of the ID field to be stored in the OID variable?
What is REAL VALUE in ifieldsvalues ?
you can not have BOTH
'insert into '||:imodulo||' '||:ifieldsvalues
'update '||:imodulo||' set '||:ifieldsvalues
because methods to specify column names and column values in INSERT and UPDATE statements is fundamentally different!!! You either would have broken update-stmt or broken insert-stmt!
The error in the above line is occurring due to syntax error
This is not enough. Show the real error text, all of it.
It includes the actual command you generate and it seems you had generated it really wrong way.
all the scan functions before inserting or updating records
Move those functions out of the SQL server and into your application server.
Then you would not have to make insert/update in that "strings splicing" way, which is VERY fragile and "SQL injection" friendly. You stepped into the road to hell here.
the error does not happen in the compilation
Exactly. And that is only for starters. You are removing all the safety checks that should had helped you in applications development.
http://searchsoftwarequality.techtarget.com/definition/3-tier-application
https://en.wikipedia.org/wiki/Multitier_architecture#Three-tier_architecture
http://bobby-tables.com
On modern Firebird versions EXECUTE STATEMENT command can have the same INTO clause as PSQL SELECT command.
https://www.firebirdsql.org/file/documentation/reference_manuals/fblangref25-en/html/fblangref25-psql-coding.html#fblangref25-psql-execstmt
Use http://translate.ru to read http://www.firebirdsql.su/doku.php?id=execute_statement
Or just see SQL examples there. Notice, however, those examples all use SELECT dynamic command, not INSERT. So I am not sure it would work that way.
This works in Firebird 2.5 (but not in Firebird 2.1) PSQL blocks.
execute statement 'insert into Z(payload) values(2) returning id' into :i;
To run it from IBExpert/FlameRobin/iSQL interactive shell add that obvious boilerplate:
execute block returns (i integer) as
begin
execute statement 'insert into Z(payload) values(2) returning id' into :i;
suspend;
end
I need to create a function, which returns results of a SELECT query. This SELECT query is a JOIN of few temporary tables created inside this function. Is there any way to create such function? Here is an example (it is very simplified, in reality there are multiple temp tables with long queries):
CREATE OR REPLACE FUNCTION myfunction () RETURNS TABLE (column_a TEXT, column_b TEXT) AS $$
BEGIN
CREATE TEMPORARY TABLE raw_data ON COMMIT DROP
AS
SELECT d.column_a, d2.column_b FROM dummy_data d JOIN dummy_data_2 d2 using (id);
RETURN QUERY (select distinct column_a, column_b from raw_data limit 100);
END;
$$
LANGUAGE 'plpgsql' SECURITY DEFINER
I get error:
[Error] Script lines: 1-19 -------------------------
ERROR: RETURN cannot have a parameter in function returning set;
use RETURN NEXT at or near "QUERY"Position: 237
I apologize in advance for any obvious mistakes, I'm new to this.
Psql version is PostgreSQL 8.2.15 (Greenplum Database 4.3.12.0 build 1)
The most recent version of Greenplum Database (5.0) is based on PostgreSQL 8.3, and it supports the RETURN QUERY syntax. Just tested your function on:
PostgreSQL 8.4devel (Greenplum Database 5.0.0-beta.10+dev.726.gd4a707c762 build dev)
The most probable error this could raise in Postgres:
ERROR: column "foo" specified more than once
Meaning, there is at least one more column name (other than id which is folded to one instance with the USING clause) included in both tables. This would not raise an exception in a plain SQL SELECT which tolerates duplicate output column names. But you cannot create a table with duplicate names.
The problem also applies for Greenplum (like you later declared), which is not Postgres. It was forked from PostgreSQL in 2005 and developed separately. The current Postgres manual hardly applies at all any more. Look to the Greenplum documentation.
And psql is just the standard PostgreSQL interactive terminal program. Obviously you are using the one shipped with PostgreSQL 8.2.15, but the RDBMS is still Greenplum, not Postgres.
Syntax fix (for Postgres, like you first tagged, still relevant):
CREATE OR REPLACE FUNCTION myfunction()
RETURNS TABLE (column_a text, column_b text) AS
$func$
BEGIN
CREATE TEMPORARY TABLE raw_data ON COMMIT DROP AS
SELECT d.column_a, d2.column_b -- explicit SELECT list avoids duplicate column names
FROM dummy_data d
JOIN dummy_data_2 d2 using (id);
RETURN QUERY
SELECT DISTINCT column_a, column_b
FROM raw_data
LIMIT 100;
END
$func$ LANGUAGE plpgsql SECURITY DEFINER;
The example wouldn't need a temp table - unless you access the temp table after the function call in the same transaction (ON COMMIT DROP). Else, a plain SQL function is better in every way. Syntax for Postgres and Greenplum:
CREATE OR REPLACE FUNCTION myfunction(OUT column_a text, OUT column_b text)
RETURNS SETOF record AS
$func$
SELECT DISTINCT d.column_a, d2.column_b
FROM dummy_data d
JOIN dummy_data_2 d2 using (id)
LIMIT 100;
$func$ LANGUAGE plpgsql SECURITY DEFINER;
Not least, it should also work for Greenplum.
The only remaining reason for this function is SECURITY DEFINER. Else you could just use the simple SQL statement (possibly as prepared statement) instead.
RETURN QUERY was added to PL/pgSQL with version 8.3 in 2008, some years after the fork of Greenplum. Might explain your error msg:
ERROR: RETURN cannot have a parameter in function returning set;
use RETURN NEXT at or near "QUERY" Position: 237
Aside: LIMIT without ORDER BY produces arbitrary results. I assume you are aware of that.
If for some reason you actually need temp tables and cannot upgrade to Greenplum 5.0 like A. Scherbaum suggested, you can still make it work in Greenplum 4.3.x (like in Postgres 8.2). Use a FOR loop in combination with RETURN NEXT.
Examples:
plpgsql error "RETURN NEXT cannot have a parameter in function with OUT parameters" in table-returning function
How to use `RETURN NEXT`in PL/pgSQL correctly?
Use of custom return types in a FOR loop in plpgsql
I have a large query in Firebird (which I run using FlameRobin), using a parameter all over the place, but getting the query below to run will do:
SELECT * FROM customers WHERE customerid = 1234;
I want to define 1234 as a variable, say customerID, so that I can easily replace it with something else.
I've learned that I need to put this inside a EXECUTE BLOCK.
EXECUTE BLOCK
AS
DECLARE customerID INT = 1234;
BEGIN
SELECT * FROM customers WHERE customerid = :customerID
END
If of any importance, the error I am getting is Engine Message :
Dynamic SQL Error
SQL error code = -104
Unexpected end of command - line 3, column 26
The problem is that FlameRobin needs to know when a statement ends and the next statement starts. By default it uses the semicolon (;) for this. However an EXECUTE BLOCK is essentially a stored procedure that isn't stored in the database, so it contains PSQL code that also uses the semicolon as a statement separator.
The consequence of this is that you get syntax errors because FlameRobin is sending incomplete statements to the server (that is: it is sending a statement after each ; it encounters).
You need to instruct FlameRobin to use a different statement terminator using SET TERM. Other Firebird query tools (eg isql) require this as well, but it is not actually part of the syntax of Firebird itself!
So you need to execute your code as:
-- Instruct flamerobin to use # as the terminator
SET TERM #;
EXECUTE BLOCK
AS
DECLARE customerID INT = 1234;
BEGIN
SELECT * FROM customers WHERE customerid = :customerID;
END#
-- Restore terminator to ;
SET TERM ;#
However doing this will still result in an error, because this query is invalid for PSQL: A SELECT in a PSQL block requires an INTO clause to map the columns to variables. And to get the values out of the EXECUTE BLOCK returned to FlameRobin you also need to specify a RETURNS clause as described in the documentation of EXECUTE BLOCK:
-- Instruct flamerobin to use # as the terminator
SET TERM #;
EXECUTE BLOCK
RETURNS (col1 INTEGER, col2 VARCHAR(100))
AS
DECLARE customerID INT = 1234;
BEGIN
SELECT col1, col2 FROM customers WHERE customerid = :customerID INTO :col1, :col2;
SUSPEND;
END#
-- Restore terminator to ;
SET TERM ;#
As far as I know the SUSPEND is technically not required here, but Flamerobin will not fetch the returned row if it isn't included.
However the above will not work if the select produces multiple rows. For that you need to use FOR SELECT ... DO combined with a SUSPEND:
-- Instruct flamerobin to use # as the terminator
SET TERM #;
EXECUTE BLOCK
RETURNS (col1 INTEGER, col2 VARCHAR(100))
AS
DECLARE customerID INT = 1234;
BEGIN
FOR SELECT col1, col2 FROM customers WHERE customerid = :customerID INTO :col1, :col2
DO
SUSPEND;
END#
-- Restore terminator to ;
SET TERM ;#
The SUSPEND here returns the row and waits until the caller has fetched that row and then continues with the FOR loop. This way it will iterate over the results.
IMHO this too much effort for parameterization. You might want to consider simply not parametrizing when you use FlameRobin, or use a tool that supports asking for parameter values for the normal parameter placeholders of Firebird (but to be honest I am not sure if there are any).
Well you need a input and return value, ex:
EXECUTE BLOCK (p_customerID integer=?)
returns(col_1 type of column table.id_cv)
as
begin
for
select col_1 from table
where customerID=:p_customerID
into col_1 do
suspend;
end
Delphi as client side:
myquery1.ParamByName('p_customerID ').Value:=1234;
myquery1.Open()
if not myquery1.IsEmpty then
begin
// using returning values
if myquery1.FieldbyName('col_1').AsString='this' then DoThat();
end;
Use this way ever yout need input parameters and/or returning values;