I'm using a stored procedure with some session tables. Everything worked fine until I've tested my stored procedure with new data.
The cursor used to retrieve data outside the session table returns the records as expected however when the same cursor is used with a session table nothing is being written in the session table.
INSERT INTO SESSION.TEMP_UNTIL (CUSTOMID, UNTIL)
WITH PERIODS AS (
SELECT NAT.UNTIL FROM TOPM.NATIONALITYHIST NAT WHERE NAT.CUSTOMID = custId
UNION
SELECT CIVIL.UNTIL FROM TOPM.MARITALSTATUSHIST CIVIL WHERE CIVIL.CUSTOMID = custId
UNION
SELECT COUNTRY.UNTIL FROM TOPM.COUNTRYOFRESIDENCEHIST COUNTRY WHERE COUNTRY.CUSTOMID = custId
)
SELECT custId, PERIODS.UNTIL FROM PERIODS ORDER BY PERIODS.UNTIL ASC;
What could be the reason for such a behavior, how can the above behavior be avoided?
The temporary table is declared as follows:
DECLARE GLOBAL TEMPORARY TABLE TEMP_UNTIL (
CUSTOMID VARCHAR(36), UNTIL DATE
)
The default for DECLARE GLOBAL TEMOPORARY TABLE is DELETE ON COMMIT, so the rows only exist in the temporary table for the life of your transaction.
You either need to perform all work within the scope of a single transaction, or add an ON COMMIT PRESERVE ROWS clause to your DECLARE GLOBAL TEMPORARY TABLE statement. For example:
DECLARE GLOBAL TEMPORARY TABLE TEMP_UNTIL (
CUSTOMID VARCHAR(36), UNTIL DATE
)
ON COMMIT PRESERVE ROWS
NOT LOGGED;
What's the result of the following select count(1) ... statements as is and with uncommented on commit preserve rows line, when you run the script with autocommit switched off in your client tool?
declare global temporary table session.tables as
(
select * from syscat.tables
)
definition only
with replace
--on commit preserve rows
not logged;
insert into session.tables
select * from syscat.tables;
select count(1) from session.tables;
commit;
select count(1) from session.tables;
Related
I've been doing research and trying things out a bunch of different ways, but with no success. I want to create a temporary table and then as I'm doing some searches, fill it up with stuff. I was able to do this with SQL Server by just declaring a table inside the procedure, but with Postgresql I've read I need to create a temporary table specifically.
My strategy started out with just
CREATE TEMP TABLE myTempTable
(
propOne bigint,
propTwo smallint,
createdAtUtc timestamp(6)
);
I even moved it to right after the "BEGIN". Down the file I get this error:
ERROR: "myTempTable" is not a known variable
LINE 77: SELECT * INTO myTempTable from myResult;
Next, I tried to create the temp table when I'm ready to fill it...
WITH some_updated_records AS
(
UPDATE dbTable
SET tablePropertyStatus = 3
WHERE tablePropertyDate < storedProcedurePropertyDate
RETURNING *
)
CREATE TEMP TABLE myTempTable as
(
SELECT *
FROM some_updated_records
);
I still get the same basic error above, but zero errors until it encounters the myTempTable variable.
I'm definitely not a SQL genius (perhaps, eventually, with your help), so there might be some other things I'm doing wrong. My whole task is to convert a SQL Server stored procedure to Postgresql.
What could I being doing wrong to make that temporary table variable un-declared? Is there a special way I need to declare it ahead of time? Am I making a mistake about how to create or declare a temporary table.
Another strategy could be to just keep saving records into a collection of types, forget the "temp table." Is there a way to do this in plpgsql?
UPDATE w/Examples
This version doesn't work. It stops at the create table.
CREATE OR REPLACE PROCEDURE MyTestProcedure(
p_Endpoint Varchar(256),
p_ContentType Varchar(200),
MaxInProcess int = NULL)
LANGUAGE plpgsql
AS $body$
DECLARE
v_UtcNow timestamp(6);
v_ExpiredProcessing timestamp(6);
BEGIN
SELECT CURRENT_TIMESTAMP into v_UtcNow at time zone 'utc';
WITH first_updated AS (UPDATE MyTable
SET Status = 1
WHERE UpdatedAtUtc < v_UtcNow
RETURNING Id, Status, UpdatedAtUtc)
CREATE TEMP TABLE IF NOT EXISTS statustable AS (SELECT Id, Status, UpdatedAtUtc FROM first_updated)
WITH m_result AS (UPDATE MyTable
SET Status = 3,
WHERE ExpirationDateTimeUtc < v_UtcNow
RETURNING Id, Status, UpdatedAtUtc)
INSERT INTO statustable from m_result;
DROP TABLE statustable;
END;
$body$
This errors out at the table creation.
INE 22: CREATE TEMP TABLE statustable as...
The other example would be something similar to creating the table first and then inserting into it. That's probably where I messed up. Working solution will be added in a minute, if someone doesn't add it in first.
You can use a CTE, but put the CTE within the parentheses for the table creation.
CREATE TEMPORARY TABLE myTempTable AS (
WITH cte_updated_records AS (
UPDATE dbTable
SET tablePropertyStatus = 3
WHERE tablePropertyDate < storedProcedurePropertyDate
RETURNING *
)
SELECT * FROM cte_updated_records
);
https://www.postgresql.org/docs/14/plpgsql-statements.html#PLPGSQL-STATEMENTS-ASSIGNMENT1
Please refer the Tip section:
Tip Note that this interpretation of SELECT with INTO is quite
different from PostgreSQL's regular SELECT INTO command, wherein the
INTO target is a newly created table. If you want to create a table
from a SELECT result inside a PL/pgSQL function, use the syntax CREATE
TABLE ... AS SELECT.
based on this then you can do
CREATE TEMP TABLE statustable AS (here is your query clause)
Maybe you can do update later.
Another Point is as per manual, seems you cannot do CREATE Table by using CTE.
Each auxiliary statement in a WITH clause can be a SELECT, INSERT,
UPDATE, or DELETE; and the WITH clause itself is attached to a primary
statement that can also be a SELECT, INSERT, UPDATE, or DELETE.
https://www.postgresql.org/docs/current/queries-with.html
LukStorms's answer is pretty neat. But serval steps maybe more readable?
When you're debugging, things can get a little crazy. What happens often, I find, is I try one good solution, but I don't know how to implement it quite right, so the following works. I think I was forgetting the select in the INSERT INTO's.
CREATE OR REPLACE PROCEDURE MyTestProcedure(
p_Endpoint Varchar(256),
p_ContentType Varchar(200),
MaxInProcess int = NULL)
LANGUAGE plpgsql
AS $body$
DECLARE
v_UtcNow timestamp(6);
v_ExpiredProcessing timestamp(6);
BEGIN
SELECT CURRENT_TIMESTAMP into v_UtcNow at time zone 'utc';
CREATE TEMP TABLE status_table(
Id bigint,
Status smallint,
CreatedAtUtc timestamp(6));
WITH first_updated AS (UPDATE MyTable
SET Status = 1
WHERE UpdatedAtUtc < v_UtcNow
RETURNING Id, Status, UpdatedAtUtc)
INSERT INTO status_table
SELECT Id, Status, UpdatedAtUtc
FROM first_updated;
WITH m_result AS (UPDATE MyTable
SET Status = 3
WHERE ExpirationDateTimeUtc < v_UtcNow
RETURNING Id, Status, UpdatedAtUtc)
INSERT INTO status_table
select Id, Status, UpdatedAtUtc
from m_result;
DROP TABLE status_table;
END;
$body$
I'm successfully inserting values from Table Variable into new (not yet existing table) Temp Table. Have not issues when inserting small number of rows (eg. 10,000), but when inserting into a Table Variable a lot of rows (eg. 30,000) is throws an error "Server ran out of memory and external resources).
To walk around the issue:
I split my (60,000) Table Variable rows into small batches (eg. 10,000) each, thinking I could insert new data to already existing Temp Table, but I'm getting this error message:
There is already an object named '##TempTable' in the database.
My code is:
USE MyDataBase;
Go
Declare ##TableVariable TABLE
(
[ID] bigint PRIMARY KEY,
[BLD_ID] int NOT NULL
-- 25 more columns
)
Insert Into ##TableVariable VALUES
(1,25),
(2,30)
-- 61,000 more rows
Select * Into #TempTable From ##TableVariable;
Select Count(*) From #TempTable;
Below is the error message I'm getting
The problem is that SELECT INTO wants to create the destination table, so at second run you get the error.
first you have to create the #TempTable:
/* this creates the temptable copying the #TableVariable structure*/
Select *
Into #TempTable
From #TableVariable
where 1=0;
now you can loop through your batches and call this insert as many times you want..
insert Into #TempTable
Select * From #TableVariable;
pay attention that #TempTable is different from ##TempTable ( # = Local, ## = Global ) and remember to drop it when you have finished.
also you should NOT use ## for you table variable, use only #TableVariable
I hope this help
This is probably a very simple question, but my attempts to search for an answer are thwarted by Google finding answers showing how to reuse a query by making a stored procedure instead. I want to reuse the results of a query inside a stored procedure.
Here's a cut-down example where I've chopped out NOCOUNT, XACT_ABORT, TRANSACTION, TRY, and much of the logic.
CREATE PROCEDURE Do_Something
#userId UNIQUEIDENTIFIER
AS
BEGIN
DELETE FROM LikedItems
WHERE likedItemId IN
(
SELECT Items.id FROM Items
WHERE Items.userId = #userId
)
DELETE FROM FollowedItems
WHERE followedItemId IN
(
SELECT Items.id FROM Items
WHERE Items.userId = #userId
)
END
What is the syntax to reuse the results of the duplicated nested SELECT rather than doing it twice?
You can INSERT result of the SELECT into a temporary table or table variable, but it doesn't automatically mean that the overall performance would be better. You need to measure it.
Temp Table
CREATE PROCEDURE Do_Something
#userId UNIQUEIDENTIFIER
AS
BEGIN
CREATE TABLE #Temp(id int);
INSERT INTO #Temp(id)
SELECT Items.id
FROM Items
WHERE Items.userId = #userId;
DELETE FROM LikedItems
WHERE likedItemId IN
(
SELECT id FROM #Temp
)
DELETE FROM FollowedItems
WHERE followedItemId IN
(
SELECT id FROM #Temp
)
DROP TABLE #Temp;
END
Table variable
CREATE PROCEDURE Do_Something
#userId UNIQUEIDENTIFIER
AS
BEGIN
DECLARE #Temp TABLE(id int);
INSERT INTO #Temp(id)
SELECT Items.id
FROM Items
WHERE Items.userId = #userId;
DELETE FROM LikedItems
WHERE likedItemId IN
(
SELECT id FROM #Temp
)
DELETE FROM FollowedItems
WHERE followedItemId IN
(
SELECT id FROM #Temp
)
END
You can declare a table variable to store the results of the select and then simply query that.
CREATE PROCEDURE Do_Something
#userId UNIQUEIDENTIFIER
AS
BEGIN
DECLARE #TempItems TABLE (id int)
INSERT INTO #TempItems
SELECT Items.id FROM Items
WHERE Items.userId = #userId
DELETE FROM LikedItems
WHERE likedItemId IN
(
SELECT id FROM #TempItems
)
DELETE FROM FollowedItems
WHERE followedItemId IN
(
SELECT id FROM #TempItems
)
END
If the subquery is fast and simple - no need to change anything. Item's data is in the cache (if it was not) after the first query, locks are obtained. If the subquery is slow and complicated - store it into a table variable and reuse by the same subquery as listed in the question.
If your question is not related to performance and you are beware of copy-paste: there is no copy-paste. There is the same logic, similar structure and references - yes, you will have almost the same query source code.
In general, it is not the same. Some rows could be deleted from or inserted into Items table after the first query unless your are running under SERIALIZABLE isolation level. Many different things could happen during first delete, between first and second delete statements. Each delete statement also requires it's own execution plan - thus all the information about tables affected and joins must be provided to SERVER anyway. You need to filter by the same source again - yes, you provide subquery with the same source again. There is no "twice" or "reuse" of a partial code. Data collected by a complicated query - yes, it can be reused (without running the same complicated query - by simple querying from prepared source) via temp tables/table variables as mentioned before.
I want to declare a Table Variable in my stored procedure using existing tables schema.
I have a Table, say TableA, which has about 30 columns.
I want to declare a Table Variable using the same columns just as we declare a Temporary Table.
For instance,
I can declare a Temporary Table using the schema like this:
SELECT TOP 0 * INTO #Temp_TableA FROM TableA
Can I similarly declare a Table Variable???
From MSDN:
No, table variable is a variable as name suggests so you need to declare it before you can use it like all other T-SQL variables and you need to use INSERT INTO
DECLARE #MyTable TABLE(
ID INT NOT NULL,
Data varchar(30) NOT NULL
);
INSERT INTO #MyTable
SELECT ID, data
From <table>
You can also use a temporary table in your stored procedure. Just add to the beginning of stored procedure this code:
if object_id('tempdb..#TableA') is not null drop table #TableA
You should use a CTE for this purpose:
; with CTE as (SELECT TOP 0* FROM TableA)
SELECT * FROM CTE
The only thing to remember is CTE can only be used in the next line after the initialization. So for example, the following won't work-
; with CTE as (SELECT TOP 0* FROM TableA)
SELECT * FROM TableA
SELECT * FROM CTE
because here CTE will become invalid.
DECLARE A Table Variable having same as SCHEMA of your table first and then INSERT INTO syntax as mentioned by Megatron.
If you are planning to use inside a stored procedure, then use CTE and don't forget to mention ; befire CTE declareation and insert into CTE variable from your table.
I need something like that which is of course not working.
insert into Table1
(
Id,
Value
)
select Id, value from
(
exec MySPReturning10Columns
)
I wanted to populate Table1 from result set returned by MySPReturning10Columns. Here the SP is returning 10 columns and the table has just 2 columns.
The following way works as long as table and result set from SP have same number of columns but in my case they are not same.
INSERT INTO TableWith2Columns
EXEC usp_MySPReturning2Columns;
Also, I want to avoid adding "." as linked server just to make openquery and openrowset work anyhow.
Is there a way not to have define table strucutre in temp table (all columns with datatypes and lenght)? Something like CTE.
You could use a temporary table as a go-between:
insert into #TempTable exec MySP
insert into Table1 (id, value) select id, value from #TempTable
You could solve the problem in two steps by doing the insert from the stored procedure into a temporary table, then do the insert selecting just the columns you want from the temporary table.
Information on temporary tables: http://www.sqlteam.com/article/temporary-tables
-- Well, declare a temp table or a table var, depending on the number of rows expected
-- from the SP. This table will be basically the result set of your SP.
DECLARE #spResult AS TABLE
(
ID INT,
VALUE FLOAT,
....
);
-- Get the result set of the SP into the temp table.
INSERT #spResult EXEC STORED_PROC;
-- Now you can query the SP's result set for ID and Value;
INSERT Table1 (ID, VALUE)
SELECT ID, VALUE FROM #spResult;
You dont need to create a temporary table, you can do it with single query by creating temporary view like this
with tempView as EXEC MySPReturning10Columns insert into Table1 select id, value from tempView
The temporary view disappears as soon as the statement finishes execution