I am inside a SQLScript procedure and would like to return the last SQL Statement from this procedure, like the last rowcount:
/********* Begin Procedure Script ************/
BEGIN
select 1 as "my_data" from dummy;
select '::last_SQL' as "last executed sql" from dummy;
select ::ROWCOUNT as "rowcount" from dummy;
END;
/********* End Procedure Script ************/
The column "last executed SQL" should be populated with select 1 as "my_data" from dummy in this case. Is there any variable holding the last statement (or any easy way to retrieve the query plan)?
Maybe you can query sys.m_sql_plan_cache system view
Please check following SELECT statement
select
statement_string, last_execution_timestamp
from SYS.M_SQL_PLAN_CACHE
where user_name = 'KODYAZ'
order by last_execution_timestamp desc;
I believe you can improve the query by introducing new filter criteria.
There is no way to programmatically get the last executed SQL statement in SQLScript. This is due to the fact that not all statements will be executed in the form and order as they appear in the source code.
If you want to analyse the performance of a procedure, you can run PlanViz against the procedure call. Generally, there is no such thing as "the performance of a procedure/function" as they always occur in a specific context.
If used within a SQL query, things like query-transformation can radically change the way certain results are computed.
Related
I want to execute two different queries based on date from an sql file.
Suppose I have two merge queries , Merge query 1, Merge query 2.
Most importantly this has to be within an sql file and run from a script using sqlplus.
Condition is like this,
If current date is "April 1st"
Execute Merge query 1
For all other dates
Execute Merge query 2
I want to avoid stored procedure. This is in Oracle
The sqlplus doesn't provide flow control (like IF statement) so the cleanest option is to use pl/sql block in the SQL script. Not a stored procedure just embed the whole logic into anonymous pl/sql block
DECLARE
...
BEGIN
END;
/
You go with selecting current date into a variable.
SELECT TO_CHAR(sysdate, 'YYYY-MM-DD') INTO some_var FROM DUAL
And execute queries inside of regular IF statement.
I am trying to use a simple IF ELSE query to test a feature with DB2 SQL. However when I attempt to execute it, I run into an error stating that I am not allowed to execute DDL statements.
What is throwing me off is that as far as I know, only database structure altering statements are considered DDL statements.
What gives?
Code:
IF 'True' = 'True' THEN
SELECT * FROM RM_TRANSACTION
FETCH FIRST 2 ROWS ONLY
FOR READ ONLY WITH UR
ELSE
SELECT * FROM RM_TRANSACTION
FETCH FIRST 4 ROWS ONLY
FOR READ ONLY WITH UR
END IF
https://imgur.com/a/58RYjpu
The problem is that you can’t ‘select to nowhere’ in a compound statement in DB2. Db2 CLP can return you the result set of a single sql statement, but it doesn’t try to do the same for select statements in a compound statement.
If you want to print the result set from a select statement in a compound statement, you can, for example, declare a cursor, fetch it in a loop, and use dbms_output.put_line calls to print the values of variables.
I've a problem executing a Stored Procedure in Informix. I'm doing a simple query that it doesn't work. This is the query:
SELECT
first 1 field1,
date1
FROM
historia_t
WHERE
field3 = 1
AND field4 = 1
AND date1 BETWEEN (CURRENT - 1 UNITS YEAR) AND CURRENT
ORDER BY
field1 desc
If I execute the query in DbVisualizer I don't have any problem but if I execute the query in Informix(With stored procedures) I get a sintaxis error in the line with " AND date1 BETWEEN (CURRENT - 1 UNITS YEAR) AND CURRENT " . But the real problem it's in ORDER BY field1 desc;
I don't know why, but sometimes Stored Procedures return errors when you use Order by in them.
Note: Fields are invented because I think they aren't important for the problem.
Thanks in advanced!
When you run a SELECT statement via DB-Access or equivalent, the program takes care of creating a cursor, opening it, fetching the data, closing the cursor, and freeing up the resources used.
Inside a stored procedure, you have to manage this processing. The FOREACH loop does that automatically. If you're using dynamic SQL, there are other statements you can use.
If a SELECT statement may return more than one row, you need the cursor management. If the SELECT statement returns just a single row, you can specify which variable should receive the result. I observe that ORDER BY is immaterial when the SELECT returns a single row — if you have an ORDER BY, there'll be a strong presumption that the query might return more than one row.
For example, this stored procedure works (and returns syssynonyms):
create procedure fk2() returning varchar(128) as tabname;
define t varchar(128);
select tabname into t from informix.systables where tabid = 9;
return t;
end procedure;
But where there's more than one row, you need:
create procedure fk3() returning varchar(128) as tabname;
define t varchar(128);
foreach select tabname into t
from informix.systables
where tabid between 4 and 10
order by tabname # No semicolon permitted (don't ask!)
return t with resume;
end foreach;
end procedure;
This returns:
syscolauth
sysdepend
syssynonyms
syssyntable
systabauth
sysusers
sysviews
I have a requirement where-in I need to read a table (table name provided as input parameter of the SP), store the results in a temp table and then store the count of the read table into a variable. Please advise how can this be achieved. I have been able to read the table and its count using dynamic query but am not able to put the results in a temp table/ variable. 'Select' and 'Into' clauses do not seem to be working with 'Execute Immediate'. Thanks.
It is not very clear to me exactly what is being asked, but you should be able to execute a SELECT statement in the following manner:
CREATE PROCEDURE p1(IN tablename VARCHAR) AS
BEGIN
execute immediate 'SELECT * FROM ' || :tablename;
END;
Then the following statements create a table and call the procedure to retrieve the result:
create table T (i integer);
insert into T values (123);
The following would produce a result set with one row/column with the value 123:
CALL p1('T')
Please note that with this type of functionality, you need to be very careful not to allow any user-provided input to be given directly to a procedure that uses EXECUTE IMMEDIATE to avoid the possibility of SQL injection attacks.
I'd like to use a stored procedure to define the IN clause of a select statement.
This is (a simplified version of) what I'm trying to do:
SELECT *
FROM myTable
WHERE columnName IN (CALL myStoredProc)
myStoredProc performs some complicated logic in the database and returns a list of possible matching values for columnName. The statement above does not work obviously. The select statement may be performed in another stored procedure if that makes a difference.
Is this at all possible in mySQL?
What return type does your current stored procedure have? You are speaking of "a list", so TEXT?
Maybe there's an easier way, but one thing you can do (inside another stored procedure) is to build another query.
To do that, we need to work around two limitations of MySQL: a) To execute dynamic SQL inside a stored procedure, it needs to be a prepared statement. b) Prepared statements can only be created out of user variables. So the complete SQL is:
SET #the_list = myStoredProc();
SET #the_query = CONCAT('SELECT * FROM myTable WHERE columnName IN (' , #the_list , ')');
PREPARE the_statement FROM #the_query;
EXECUTE the_statement;
If you're talking about returning a result set from a stored routine and then using it as table, that is not possible. You need to make a temporary table to work around this limitation.