Being a recent convert from SQL Server, I am getting to know Postgresql a bit.
I really hate having to write nested selevt statements in SQL since I find that the readability and maintainability of the code suffers when I do.
Usually I would create a stored procedure in SQL Server where I would select something into a temporary table, that I can then use in another select statement.
CREATE OR ALTER PROCEDURE Procname
AS
BEGIN
SELECT
Somewhere.Col_1,
Somewhere.Col_2
INTO
#Temptable
FROM
Somewhere Somewhere
SELECT
Temptable.Col_1,
Somewhere_Else.Col3
FROM
#Temptable Temptable
INNER JOIN
Somewhere_Else.Col_2 = Temptable.Col_2
END
When I execute this procedure I would get returned the final select query
How would I replicate this procedure in Postgresql?
I know that you can select into a temporary table, but I cannot seem to figure out how to use this table in the next select statement within the same procedure
Create a set returning function, there is no need for a temp table at all.
CREATE function Procname()
returns table(col_1 ???, col2 ???) --<< change data types here
AS
$$
SELECT
Temptable.Col_1,
Somewhere_Else.Col3
FROM Somewhere Temptable
INNER JOIN Somewhere_Else ON Somewhere_Else.Col_2 = Temptable.Col_2;
$$
language sql
stable;
But for such a simple statement, I would rather create a view.
Related
set serveroutput on;
CREATE OR REPLACE PROCEDURE test_migrate
(
--v_into_table dba_tables.schema#dbprd%TYPE,
--v_from_table dba_tables.table#dbprd%TYPE,
v_gid IN NUMBER
)
IS
BEGIN
select * INTO fx.T_RX_TXN_PLAN
FROM fx.T_RX_TXN_PLAN#dbprd
WHERE gid = v_gid;
--and schema = v_into_table
--and table = v_from_table;
COMMIT;
END;
I thought that SELECT * INTO would create a table in the new database from #dbprd. However, the primary issue is just being able to set these as variables and the goal is to EXEC(INTO_Table,FROM_Table,V_GID) to run the above code.
Error(9,19): PLS-00201: identifier 'fx.T_RX_TXN_PLAN' must be
declared Error(10,5): PL/SQL: ORA-00904: : invalid identifier
If your goal is to copy data from table in "another" database into a table that resides in "this" database (regarding database link you used), then it it INSERT INTO, not SELECT INTO.
For example:
CREATE OR REPLACE PROCEDURE test_migrate (v_gid in number)
IS
BEGIN
insert into fx.t_rx_txn_plan (col1, col2, ..., coln)
select col1, col2, ..., coln
from fx.t_rx_txn_plan#dbprod
where gid = v_gid;
END;
Last sentence you wrote looks like you'd want to make it dynamic, i.e. pass table names and v_gid (whatever that might be; looks like all tables that should be involved into this process have it). That isn't a simple task.
If you plan to use insert into select * from, that's OK but not for production system. What if someone alters a table and adds (or drops) a column or two? Your procedure will automatically fail. Correct way to do it is to enumerate all columns involved, but that requires fetching data from user_tab_columns (or all_ or dba_ version of the same), which complicates it even more.
Therefore, if you want to move data from here to there, why don't you do it using Data Pump Export & Import? Those utilities are designed for such a purpose, and will do the job better than your procedure. At least, I think so.
This way you should be returning a row. If so, add an OUT type parameter to the procedure with
CREATE OR REPLACE PROCEDURE test_migrate(
--v_into_table dba_tables.schema#dbprd%TYPE,
--v_from_table dba_tables.table#dbprd%TYPE,
i_gid IN NUMBER,
o_RX_TXN_PLAN OUT fx.T_RX_TXN_PLAN#dbprd%rowtype
) IS
BEGIN
SELECT *
INTO RT_RX_TXN_PLAN
FROM fx.T_RX_TXN_PLAN#dbprd
WHERE id = v_gid;
--and schema = v_into_table
--and table = v_from_table;
END;
and call the procedure such as
declare
v_rx_txn_plan fx.T_RX_TXN_PLAN#dbprd%rowtype;
v_gid number:=5345;
begin
test_migrate(v_gid => v_gid, rt_rx_txn_plan => v_rx_txn_plan);
dbms_output.put_line(v_rx_txn_plan.col1);
dbms_output.put_line(v_rx_txn_plan.col2);
end;
to print out the returning values for some columns of the table. to be able to create a new table from this, not SELECT * INTO ... syntax, but
CREATE TABLE T_RX_TXN_PLAN AS
SELECT *
INTO RT_RX_TXN_PLAN
FROM fx.T_RX_TXN_PLAN#dbprd
WHERE ...
is used.
But neither of the cases to issue a COMMIT since there's no DML exists within them.
To create a table you must use the CREATE TABLE statement, and to use any DDL statement in PL/SQL you have to use EXECUTE IMMEDIATE:
CREATE OR REPLACE PROCEDURE test_migrate
(
v_gid IN NUMBER
)
IS
BEGIN
EXECUTE IMMEDIATE 'CREATE TABLE FX.T_RX_TXN_PLAN AS
SELECT *
FROM fx.T_RX_TXN_PLAN#dbprd
WHERE gid = :GID'
USING IN v_gid;
END;
I would like to execute a stored procedure X from within the SELECT statement of stored procedure Y, so that X's value can be returned as part of Y's data.
I am trying the following syntax, but it's apparently not valid.
SELECT name, type, (EXEC X #type=type)
FROM table
As I hope you can see above, I need to pass the current row's type value to procedure X to get the proper return value.
Disclaimer: I probably just don't know what I'm doing.
The approach what you have tried is invalid. Instead of the X as the stored procedure convert it as user-defined function. like the below
Create function dbo.fnGetTypeDetail
(
#type varchar(50)
)
returns varchar(100)
As
Begin
return --do your operation;
End
And replace your query as:
SELECT name, type, dbo.fnGetTypeDetail(type) AS TypeDetail
FROM table
For sample, I created a scalar function. Based on your requirement you can create inline table valued function as per the example
You can't EXEC a stored proc inside a SELECT statement.
What you can do is INSERT..EXEC a stored proc into a temp table, and then run a SELECT statement that queries that temp table, while joining to other tables if desired.
Psuedo-example:
INSERT INTO #Tmp (Column1) EXEC X;
SELECT Name, Type, (SELECT Column1 FROM #tmp)
FROM MyTable
Is it possible to load a table from a with statement via a stored procedure in HANA? Nothing i try seems to work, and the only thing that does work when creating a procedure is just displaying the data from the with statement via a select. Below I show three examples I have tried for accessing with statement data. Currently on HANA revision 84. Please note the table create is just for purposes of the test example.
CREATE PROCEDURE test_proc
LANGUAGE SQLSCRIPT
SQL SECURITY INVOKER
AS
BEGIN
create table t1 (cal_day date);
with w1 as (
select current_date cal_day from dummy
)
--works just fine but isn't loading the data into anything
select * from w1;
--get indentifier must be declared error
select cal_day into t1 from w1;
--get incorrect syntax error
insert into t1
select cay_day from w1;
END
When you want to execute DDL statements in a SQLScript procedure you'll need to use dynamic SQL for that (EXEC).
I have two fairly large and complex stored procedures. I want to call a second stored procedure from the first stored procedure. For example:
-- stored_procedure_one
select tb1.col1, tb1.col2, sp1.col3, sp1.col4
from table1 tb1
inner join stored_procedure_two sp1 on sp1.col1 = tbl1.col1
Is something similar possible with SQL as the above script gives me an invalid object error message.
Using a temp table is not good in this example, because if I did that, it would take an hour just to fill the temp table with all the data from the second stored procedure. I only want the stored procedure to return the needed data.
This is not going to work. You cannot join on a stored procedure. However, you could consider changing stored_procedure_two into a table-valued user defined function. You could then 'join' via a Cross Apply. I have done this on numerous occasions and it works quite well.
If the second stored procedure is too large and complex, it may not be possible to convert to a UDF. In this case, I think your only alternative is to save the results of the second stored proc to a table and join on that. But that could be somewhat inefficient and messy.
You may add the results of the second procedure in a local variable table
DECLARE #Table TABLE
(
Col1 int,
Col2 ...
)
INSERT INTO #Table
EXEC stored_procedure_two
select tb1.col1, tb1.col2, sp1.col3, sp1.col4
from table1 tb1
inner join #Table tbl2 on sp1.col1 = tbl1.col1
How do I combine executing of a stored procedure and using its result or parameters in a regular SQL query?
For example I would like to do something like the following:
-- passing result of SELECT to SP
SELECT a, b FROM t
EXEC my_sp a, b
-- passing result of SP to INSERT
INSERT INTO t
EXEC my_sp a, b
etc.
no, you need to use a temp table
create table #results (col1 int, col2 varchar(5) ...)
INSERT INTO #results
EXEC YourProcedure #parma...
then you can join to it
SELECT
*
FROM YourTable y
JOIN #results r ON ...
....
if you don't know the columns and data types from the procedure you can use this excellent answer: Insert results of a stored procedure into a temporary table
In brief it uses OPENROWSET to execute the stored procedure into a #temp table that is created on the fly, without the need to name and know the type all the columns.
If your SP can be rewritten as an inline table valued UDF, these typically perform very well and are equivalent to a parametrized view. ITVF can be used any place you would use a table or view.
If your SP won't work as an inline TVF (local variable manipulation required), it may work as a multi-statement TVF (contains a BEGIN/END) which may or may not perform poorly depending on what you have to do.
After your SP has been turned into a UDF, you can then still call the UDF from your SP (SELECT* FROM udf(params)) or elsewhere it can be used for joins, etc, so all your code is inside the UDF - no duplication.