I need to run big queries (that was a part of SP) and look at their results (just trying to find a bug in a big SP with many unions. I want to break it into parts and run them separately).
How can I do that if this SP have few parameters? I don't want to replace them in code, it would be great just to add declare in a header with a hardcode for this parameter.
I've tried something like this:
DECLARE
p_asOfDate DATE := '22-Feb-2011';
BEGIN
SELECT * from myTable where dateInTable < p_asOfDate;
END
But it says that I should use INTO keyword. How can I view this results in my IDE? (I'm using Aqua data studio)
I need to do that very often, so will be very happy if will find a simple solution
You are using an anonymous block of pl/sql code.
In pl/sql procedures you need to specify a target variable for the result.
So you first need to define a variable to hold the result in the declare section
and then insert the result data into it.
DECLARE
p_asOfDate DATE := '22-Feb-2011';
p_result myTable%ROWTYPE;
BEGIN
select * into p_result from myTable where dateInTable < p_asOfDate;
END
That said you will probaply get more than one row returned, so I would use
a cursor to get the rows separately.
DECLARE
CURSOR c_cursor (asOfDate IN DATE) is
select * from myTable where dateInTable < asOfDate;
p_asOfDate DATE := '22-Feb-2011';
p_result myTable%ROWTYPE;
BEGIN
OPEN c_cursor(p_asOfDate);
loop
FETCH c_cursor into p_result;
exit when c_cursor%NOTFOUND;
/* do something with the result row here */
end loop;
CLOSE c_cursor;
END
To output the results you can use something like this for example:
dbms_output.put_line('some text' || p_result.someColumn);
Alternatively you can execute the query on an sql command-line (like sqlplus)
and get the result as a table immediately.
I hope I understood your question correctly...
update
Here is a different way to inject your test data:
Use your tools sql execution environemnt to submit your sql statement directly without a pl/sql block.
Use a "&" in front of the variable part to trigger a prompt for the variable.
select * from myTable where dateInTable < &p_asOfDate;
The Result should be displayed in a formatted way by your tool this way.
I do not know about Aqua, but some tools have functions to define those parameters outside the sql code.
Related
I would like to know if it's possible to write a sql query that returns a set of columns based on a condition.
Like for example:
If (id=='A')
{
Select id,name
From Table A
}
Else If(Condition=B)
{
Select Column1, Column3
From Table A
}
If yes please help me write it
You can do switch-like statements with CASE expressions in plain SQL. See the following example:
SELECT some_other_field,
id,
CASE ID
WHEN A THEN columnA
WHEN B THEN columnB
ELSE 'Unknown'
END genericvalue
FROM customers;
There are some limitations of course. For example the type of the return values in the THEN clause need to match, so you may need to convert for example all to char, or to int, etc.
Syntax (IF-THEN-ELSE)
The syntax is for IF-THEN-ELSE in Oracle/PLSQL is:
IF condition THEN
{...statements to execute when condition is TRUE...}
ELSE
{...statements to execute when condition is FALSE...}
END IF;
http://www.techonthenet.com/oracle/loops/if_then.php
SQL itself isn't turing-complete and it doesn't have syntax for loops and conditions: you can perform a query with it, no matter how complex it is, but you can't decide which query to execute depending on a condition or perform a query a number of times, which is what you are trying to do here.
In order to provide such functionality each database developer typically provides an additional language that includes variable declaration, loops, conditionals, etc. For Oracle this language is PL/SQL.
What you need to do in SQL Developer to solve your issue and see how PL/SQL works is create an empty script, then write something like this:
--Enabling output to the console
SET SERVEROUTPUT ON;
DECLARE
--Variable declaration block; can initialize variables here too
test_var varchar2(10);
test_result varchar2(10);
BEGIN
--Initializing variables, the first one we will check in the IF statement, the second one is just for transparency
test_var := 'test';
test_result := '';
--IF block: check some condition, perform a select based on the value, save result into a variable
IF test_var = 'test' THEN
SELECT '1' INTO test_result FROM dual;
ELSE
SELECT '2' INTO test_result FROM dual;
END IF;
--Output the result to console
DBMS_OUTPUT.PUT_LINE(test_result);
END;
Then run it with 'Run script'/F5. You will get '1' as output as you would expect. Change test_var to something else and run it again, you will get '2'.
If you have questions of this kind it might be useful to read about what exactly SQL and PL/SQL are. PL/SQL is quite efficient and versatile and can be used for anything from automating SQL scripts to implementing complex optimisation algorithms.
Of course, PL/SQL has similar constructs for FOR and WHILE loops, CASE checks, etc.
I guess this is what you are looking at.
It is not possible to do such a selection in SQL even by using CASE and DECODE.
But the best we can do is we can create a function which returns a ref_cursor and use the function in the SQL stetement to fit your requirement.
Below is an example for it:
CREATE OR REPLACE
FUNCTION test1(
id1 VARCHAR)
RETURN sys_refcursor
AS
v_ref sys_refcursor;
BEGIN
IF(id1='A') THEN
OPEN v_ref FOR SELECT id,name FROM TABLE A;
ElsIf(id1='B') THEN
OPEN v_ref FOR SELECT Column1, Column3 FROM TABLE A;
END IF;
RETURN v_ref;
END;
select test1(A) from dual;
Above will display only the columns id and name.
I've created one table "Meta_Data_Table_Names" where I inserted forty eight table names in the MetaTableName column. And there is another column to provide Row count with corresponding table name.
I wanted to fetch the table name from “Meta_Data_Table_Names” and execute SELECT Query sequentially through Loop for validation purpose.
Whenever, I execute from TOAD , It’s throwing an error:
Table or view does not exist.
Do we need to make a place holder for 'Meta_name' which can be scanned? Or any particular syntax to read the value during Query?
DECLARE
CURSOR c1 IS SELECT MetaTableName FROM Meta_Data_Table_Names;
CURSOR c2 IS SELECT ROW_COUNT FROM Meta_Data_Table_Names;
Meta_name Meta_Data_Table_Names.MetaTableName%TYPE;
Count_num Meta_Data_Table_Names.ROW_COUNT%TYPE;
BEGIN
OPEN c1;
OPEN c2;
FOR i IN 1..48 LOOP
FETCH c1 INTO Meta_name;
FETCH c2 INTO Count_num;
IF (Count_num > 2000)
THEN
SELECT * FROM Meta_Name X
MINUS
SELECT * from ASFNCWK07.Meta_Name#NCDV.US.ORACLE.COM Y
UNION ALL
SELECT * FROM ASFNCWK07.Meta_Name#NCDV.US.ORACLE.COM Y
MINUS
SELECT * FROM Meta_Name X;
ELSE
DBMS_OUTPUT.PUT_LINE ('No Validation is required');
END IF;
END LOOP;
END;
Oracle does not allow you to do queries with dynamic table names, i.e. if the table name is not known at compile time. Do do that, you need Dynamic SQL, which is a bit too broad to go into here.
There are a number of problems with your code.
Firstly, we cannot use variable names in normal SQL: for this we need dynamic SQL. For instance:
execute immediate 'select 1 from '|| Meta_Name || into n;
There are a lot of subtleties when working with dynamic SQL: the PL/SQL documentation devotes a whole chapter to it. Find out more.
Secondly, when executing SQL in PL/SQL, we need need to provide a target variable. This must match the projection of the executed query. When selecting a whole row the %ROWTYPE keyword is useful. Again the documentation covers this: find out more. Which leads to ...
Thirdly, because you're working with dynamic SQL and you don't know in advance which tables will be in scope, you can't easily declare target variables. This means you'll need to use ref cursors and/or Type 4 dynamic SQL techniques. Yikes! Read Adrian Billington's excellent blog article here.
Lastly (I think), the UNION ALL in your query doesn't allow you to identify which rows are missing from where. Perhaps that doesn't matter.
I have a stored procedure which I am running from a .sql file which takes in inputs from the users and runs the procedure. The procedure runs many queries and inserts a row of values into the table. In the .sql file I have I would like to order the table by a certain column after I finish running the queries. Currently I have:
DECLARE
NAMEPARAM VARCHAR2(200);
VERSIONPARAM VARCHAR2(200);
STARTDATE DATE;
ENDDATE DATE;
BEGIN
NAMEPARAM := '&1';
VERSIONPARAM := '&2';
STARTDATE := '&3';
ENDDATE := '&4';
PROCEDURE(NAMEPARAM, VERSIONPARAM, STARTDATE, ENDDATE);
COMMIT;
Select * from TABLE_NAME
ORDER BY COLUMN_NAME ASC;
EXCEPTION
WHEN OTHERS THEN
RAISE_APPLICATION_ERROR(-20101,SQLERRM);
END;
/
However It throws the error:
PLS-00428: an INTO clause is expected in this SELECT statement
I dont know why it needs an into clause. Help?
Edit:
To clarify I don't want to see an output of a sorted table I would like the table itself to be updated and sorted by the column in ascending order.
If you put a SELECT statement in a PL/SQL block, you need to do something with the results. If you're expecting exactly one row, you'd do a SELECT INTO a local variable. Assuming that you are expecting multiple rows, you could write a FOR loop that iterates over the rows or you could BULK COLLECT the rows into a PL/SQL collection. You could also open a SYS_REFCURSOR but since there is no way to return that from an anonymous PL/SQL block, that seems unlikely to be what you want.
My guess is that you want the SELECT statement to be outside the PL/SQL block and you want whatever tool you are using to execute the .sql script to run the PL/SQL block to populate the table and then run the SELECT statement, writing the results to whatever file/ console you are spooling output to.
I have 2 procedures inside a package. I am calling one procedure to get a comma separated list of user ids.
I am storing the result in a VARCHAR variable. Now when I am using this comma separated list to put inside an IN clause in it is throwing "ORA-01722:INVALID NUMBER" exception.
This is how my variable looks like
l_userIds VARCHAR2(4000) := null;
This is where i am assigning the value
l_userIds := getUserIds(deptId); -- this returns a comma separated list
And my second query is like -
select * from users_Table where user_id in (l_userIds);
If I run this query I get INVALID NUMBER error.
Can someone help here.
Do you really need to return a comma-separated list? It would generally be much better to declare a collection type
CREATE TYPE num_table
AS TABLE OF NUMBER;
Declare a function that returns an instance of this collection
CREATE OR REPLACE FUNCTION get_nums
RETURN num_table
IS
l_nums num_table := num_table();
BEGIN
for i in 1 .. 10
loop
l_nums.extend;
l_nums(i) := i*2;
end loop;
END;
and then use that collection in your query
SELECT *
FROM users_table
WHERE user_id IN (SELECT * FROM TABLE( l_nums ));
It is possible to use dynamic SQL as well (which #Sebas demonstrates). The downside to that, however, is that every call to the procedure will generate a new SQL statement that needs to be parsed again before it is executed. It also puts pressure on the library cache which can cause Oracle to purge lots of other reusable SQL statements which can create lots of other performance problems.
You can search the list using like instead of in:
select *
from users_Table
where ','||l_userIds||',' like '%,'||cast(user_id as varchar2(255))||',%';
This has the virtue of simplicity (no additional functions or dynamic SQL). However, it does preclude the use of indexes on user_id. For a smallish table this shouldn't be a problem.
The problem is that oracle does not interprete the VARCHAR2 string you're passing as a sequence of numbers, it is just a string.
A solution is to make the whole query a string (VARCHAR2) and then execute it so the engine knows he has to translate the content:
DECLARE
TYPE T_UT IS TABLE OF users_Table%ROWTYPE;
aVar T_UT;
BEGIN
EXECUTE IMMEDIATE 'select * from users_Table where user_id in (' || l_userIds || ')' INTO aVar;
...
END;
A more complex but also elegant solution would be to split the string into a table TYPE and use it casted directly into the query. See what Tom thinks about it.
DO NOT USE THIS SOLUTION!
Firstly, I wanted to delete it, but I think, it might be informative for someone to see such a bad solution. Using dynamic SQL like this causes multiple execution plans creation - 1 execution plan per 1 set of data in IN clause, because there is no binding used and for the DB, every query is a different one (SGA gets filled with lots of very similar execution plans, every time the query is run with a different parameter, more memory is needlessly used in SGA).
Wanted to write another answer using Dynamic SQL more properly (with binding variables), but Justin Cave's answer is the best, anyway.
You might also wanna try REF CURSOR (haven't tried that exact code myself, might need some little tweaks):
DECLARE
deptId NUMBER := 2;
l_userIds VARCHAR2(2000) := getUserIds(deptId);
TYPE t_my_ref_cursor IS REF CURSOR;
c_cursor t_my_ref_cursor;
l_row users_Table%ROWTYPE;
l_query VARCHAR2(5000);
BEGIN
l_query := 'SELECT * FROM users_Table WHERE user_id IN ('|| l_userIds ||')';
OPEN c_cursor FOR l_query;
FETCH c_cursor INTO l_row;
WHILE c_cursor%FOUND
LOOP
-- do something with your row
FETCH c_cursor INTO l_row;
END LOOP;
END;
/
Using HSQL 2.2.5 I need to shudder process one row at a time in a stored procedure, so I thought the "Iterated FOR" statement might do the trick for me. Unfortunately I don't seem to be able to make it work. It's supposed to look something like:
FOR SELECT somestuff FROM sometable DO
some random SQL statements
END FOR;
That leaves off a bit of the syntax, but it's close enough for now.
The problem seems to be that the statements inside the loop never execute. I've verified that my SELECT statement does indeed return something.
So let's get concrete. When I execute this stored procedure:
CREATE PROCEDURE b()
MODIFIES SQL DATA
BEGIN ATOMIC
DECLARE count_var INTEGER;
SET count_var = 0;
WHILE count_var < 10 DO
INSERT INTO TTP2 VALUES(count_var);
SET count_var = count_var + 1;
END WHILE;
END;
I get 10 rows inserted into table TTP2, with values 0 through 9. (TTP2 has just one column defined, of type INTEGER.)
But when I substitute a FOR statement for the WHILE like so:
CREATE PROCEDURE c()
MODIFIES SQL DATA
BEGIN ATOMIC
DECLARE count_var INTEGER;
SET count_var = 0;
FOR SELECT id FROM ttp_by_session FETCH 10 ROWS ONLY DO
INSERT INTO TTP2 VALUES(count_var);
SET count_var = count_var + 1;
END FOR;
END;
I get nothing inserted into TTP2. (I have verified that the SELECT statement returns 10 rows, one column of integers.)
When I leave the FETCH clause off I still get no results. ttp_by_session is a view, but the same thing happens with a bare table.
What am I doing wrong?
Thanks for the help.
This works fine with the latest version of HSQLDB. Try with the 2.3.0 release candidate snapshot from the HSQLDB web site.
When the FOR statement was initially added about two years ago, it had limited functionality. The functionality was extended in later versions.