I have the following MySQL routine:
DELIMITER $$
CREATE DEFINER=`root`#`%` PROCEDURE `getGroupOrders`(grp INT,
ord CHAR(20),
srt CHAR(4),
page INT,
count INT)
BEGIN
SELECT *
FROM `dbre`.`order_info`
WHERE username IN (SELECT `dbre`.`users`.`username`
FROM `dbre`.`users`
WHERE `dbre`.`users`.`id_group` = grp)
ORDER BY ord srt LIMIT page,count;
END
As you can see, I want to pass the ordering column and sorting as a parameters, however I get a syntax error is there a way to do this or do I have to make similar routines for each type of ordering?
I don't think this is possible in the way you try it.
You cannot use a variable to define the ORDER BY column an direction.
The only workaround I can think of is to create a prepared statement from a dynamically created string (where you can use the variables to specify the order by details) and then execute that prepared statement.
Here is an example of such a dynamic statement:
http://forums.mysql.com/read.php?98,393613,393642#msg-393642
Related
How do I pass multiple entries through an input parameter mapped from a Table Function in SAP HANA ?
I've written a Table Function with an Input Parameter say IN_FORMAT_CD.
I've mapped this parameter to the one created in my calculation view.
I'm able to retrieve the data when I'm passing only one value say 100.
But it gives no result when I'm passing more than one value.
Is there any workaround for the same ?
My table function :
FUNCTION "HADMIN"."RA.Test.Prathamesh::PH_DEMO" (IN IN_FORMAT_CD NVARCHAR(500))
RETURNS TABLE (NAME NVARCHAR(10), ID NVARCHAR(10), FORMAT_CD NVARCHAR(3))
LANGUAGE SQLSCRIPT
SQL SECURITY INVOKER AS
BEGIN
RETURN
SELECT NAME,ID,FORMAT_CD
FROM
HADMIN.PH_DEMO
WHERE FORMAT_CD IN (select :IN_FORMAT_CD as FORMAT_CD from dummy);
END;
What you are looking for is the APPLY_FILTER function of SAP HANA SQLScript.
The following example shows how your scenario could be coded:
create function get_vals (IN id_list varchar(400))
returns table (id bigint, val varchar(40))
as
begin
declare myfilter varchar(450) := ' ID in (' || :id_list || ')';
_tmp = select id, val from some_vals;
_tmp2 = APPLY_FILTER (:_tmp, :myfilter);
return :_tmp2;
end;
select *
from
get_vals ('1, 4, 23, 4, 23, 3');
This approach will push down the unique list of IDs to be used as a filter when reading the table data. However, this is still dynamic SQL so you lose benefits like plan sharing and risk SQL injection attacks. Read more on this e.g. here.
If possible, you want to handle selection lists in your application code.
This, in turn, would also give you the option to decide whether using IN-lists or inner joins against temporary tables is the best approach for your situation.
In case you want to go with the selection list as a string, you should at least make sure, that common SQL injection attacks are not used and that the "in-list" really only contains possible ID values and commas.
it is not possible to produce(!) many items from a single sql variable unless you split them
In your SQL subselect query will return only rows that FORMAT_CD column values are exactly same with IN_FORMAT_CD parameter.
If this parameter represents more than one value, then this parameter is a concatenated string representation of each sub items. So we can split them back.
Splitting will produce a table on the fly which can be used for selection.
Please create the user-defined HANA Split function fnsplit that source codes can be found at referenced document
Then you can alter your function as follows assuming that each value is seperated with "," from others
ALTER FUNCTION "HADMIN"."RA.Test.Prathamesh::PH_DEMO" (IN IN_FORMAT_CD NVARCHAR(500))
RETURNS TABLE (NAME NVARCHAR(10), ID NVARCHAR(10), FORMAT_CD NVARCHAR(3))
LANGUAGE SQLSCRIPT
SQL SECURITY INVOKER AS
BEGIN
RETURN
SELECT NAME,ID,FORMAT_CD
FROM
HADMIN.PH_DEMO
WHERE FORMAT_CD IN (
select str from fnsplit(:IN_FORMAT_CD,',')
);
END;
So, I have this stored procedure (let's call it SP1) that gets as parameters two strings (say string1 and string2)
However, I need to call this stored procedure a lot from my code, so in order to make things faster, I was thinking of doing it in bulk. Collecting all of the parameters into a collection of some sort, and then send this.
From what I understand I need to use a DataTable on the code side, and a custom table type as the parameter on the SQL Server side - ok, cool. But...now what?
But... how do I get from there to the point where I actually go
EXEC SP1 string1, string2 or something along those lines?
Not sure whether this is what you like to achieve, instead of parsing those two string parameters, you would like to get a table holding all of the string row?
If so, you could you use UDF within SP,
Check here:
CREATE FUNCTION [dbo].[Name]
(
#parameter
)
RETURNS #Table TABLE
(
col1 varchar(50),
col2 varchar(50)
)
AS
BEGIN
**the query that inserts each records to TABLE**
END
Then using this [Name] UDF in your SP
Create a table type
CREATE TYPE Strings AS TABLE ( String1 VARCHAR(50), String2 VARCHAR(50) )
Alter your procedure to accept table type as input
ALTER PROCEDURE Usp_procname (#strings STRINGS Readonly)
AS
..
To call the procedure
DECLARE #strings STRINGS
INSERT INTO #strings
(String1,String2)
SELECT 'String1','String2'
UNION ALL
SELECT 'String3','String4'
UNION ALL
SELECT 'String5','String6'
EXEC Usp_procname #strings
By this way you can pass more than one string in a single call. Make sure you update the logic inside the procedure to handle more than one string
In a case like this one, I usually concatenate strings and split them on the server side or pass even an xml if I have multiple columns. Sql it's very fast when processing xml. You can try all the methods and check the processing time and after that choose the best method.
Below is the sample procedure code,
create or replace procedure pro_test(start_date date, end_date date)
is
begin
insert into test1 select col1, col2, col3 from main where range_date between start_date and end_date;
exception
< what are the exception I need to capture >
end;
/
Q1 : Is this right way to pass date directly inside the procedure?
Q2 : If not, can I pass varchar inside the procedure , to convert the date in declaration part?
Q3 : In begin part am using between operator, can i pass procedure parameter directly ?
While executing this procedure, exec pro_test('10102015','30102015'); What i need to mention in between sentence? between start_date and end_date is this enough or i need to mask date format?
can someone help me to clear on this?
Q1 : Is this right way to pass date directly inside the procedure?
Yes.
Q3 : In begin part am using between operator, can i pass procedure parameter directly ?
Not sure what you mean by this, but your insert statement is fine. You are passing a DATE as parameter and inserting into the table.
In my opinion, all this could be done in a single INSERT..SELECT statement in pure SQL.
insert into test1
select col1, col2, col3
from main
where range_date
between TO_DATE(<date_literal>,<format mask>)
and TO_DATE(<date_literal>,<format mask>);
UPDATE Per OP's comment:
While executing this procedure, exec pro_test('10102015','30102015');
What i need to mention in between sentence? between start_date and
end_date is this enough or i need to mask date format?
'10102015' is not a DATE, it is a string literal. You must pass it as DATE, so you must either use TO_DATE with proper format mask or ANSI Date literal as you do not have any time portion. ANSI Date literal uses a fixed format 'YYYY-MM-DD'.
For example,
Using TO_DATE:
EXEC pro_test(TO_DATE('10102015','DDMMYYYY'),TO_DATE('30102015','DDMMYYYY'));
Using ANSI Date literal:
EXEC pro_test(DATE '2015-10-10', DATE '2015-10-30');
Q1. You need say procedure what type of parameters input or output(adding in or out), for your procedure it is input:
create or replace procedure pro_test(start_date in date, end_date in date)
Everything else in your procedure fine.
If you want to be extra cautious, you should namespace your pl/sql variables when they are used in a SQL statement:
create or replace procedure pro_test(start_date date, end_date date)
is
begin
insert into test1
select col1, col2, col3
from main where range_date
between pro_test.start_date and pro_test.end_date;
...
This prevents the SQL engine "capturing" the variables if their name is the same as a column in a referenced table.
Commonly you see people try to avoid this with:
create procedure my_procedure (p_customer_id number)
...
where customer_id = p_customer_id
Namespacing the variables allows you to keep a cleaner interface without the prefixing.
I'm trying to create a function that takes the parameters for the column, the table, the limit, and offset. Basically, I want to be able to get a specified number of rows data from a specified table from a specified column.
However, I'm unable to get the following code to work - I get several errors such as:
syntax error, unexpected SELECT, expecting ':' in: "create function get_banana(lim int, off int, tbl varchar(32), col varchar(32)) r"
syntax error, unexpected RETURN in: "return"
syntax error, unexpected END in: "end"
These errors seem kind of meaningless.
My code is as follows:
CREATE FUNCTION GET_BANANA(lim int, off int, tbl varchar(32), col varchar(32))
RETURNS TABLE (clm int)
BEGIN
PREPARE SELECT col FROM tbl LIMIT ? OFFSET ?;
RETURN EXEC (lim, off);
END;
I'd appreciate any help :) Thanks!
I see at least two issues
EXEC needs the identifier that is returned by PREPARE, e.g.:
sql>prepare select * from tables;
execute prepared statement using: EXEC 2(...)
sql>exec 2();
The function parameters tbl and col are string values. You cannot use them as table/column identifiers.
Having said that, I am not even sure if PREPARE can be used inside a function.
No, PREPARE is a top-level statement modifier.
Scenario
I have a stored procedure written in T-Sql using SQL Server 2005.
"SEL_ValuesByAssetName"
It accepts a unique string "AssetName".
It returns a table of values.
Question
Instead of calling the stored procedure multiple times and having to make a database call everytime I do this, I want to create another stored procedure that accepts a list of all the "AssetNames", and calls the stored procedure "SEL_ValueByAssetName" for each assetname in the list, and then returns the ENTIRE TABLE OF VALUES.
Pseudo Code
foreach(value in #AllAssetsList)
{
#AssetName = value
SEL_ValueByAssetName(#AssetName)
UPDATE #TempTable
}
How would I go about doing this?
It will look quite crippled with using Stored Procedures. But can you use Table-Valued Functions instead?
In case of Table-Valued functions it would look something like:
SELECT al.Value AS AssetName, av.* FROM #AllAssetsList AS al
CROSS APPLY SEL_ValuesByAssetName(al.Value) AS av
Sample implementation:
First of all, we need to create a Table-Valued Parameter type:
CREATE TYPE [dbo].[tvpStringTable] AS TABLE(Value varchar(max) NOT NULL)
Then, we need a function to get a value of a specific asset:
CREATE FUNCTION [dbo].[tvfGetAssetValue]
(
#assetName varchar(max)
)
RETURNS TABLE
AS
RETURN
(
-- Add the SELECT statement with parameter references here
SELECT 0 AS AssetValue
UNION
SELECT 5 AS AssetValue
UNION
SELECT 7 AS AssetValue
)
Next, a function to return a list AssetName, AssetValue for assets list:
CREATE FUNCTION [dbo].[tvfGetAllAssets]
(
#assetsList tvpStringTable READONLY
)
RETURNS TABLE
AS
RETURN
(
-- Add the SELECT statement with parameter references here
SELECT al.Value AS AssetName, av.AssetValue FROM #assetsList al
CROSS APPLY tvfGetAssetValue(al.Value) AS av
)
Finally, we can test it:
DECLARE #names tvpStringTable
INSERT INTO #names VALUES ('name1'), ('name2'), ('name3')
SELECT * FROM [Test].[dbo].[tvfGetAllAssets] (#names)
In MSSQL 2000 I would make #allAssetsList a Varchar comma separated values list. (and keep in mind that maximum length is 8000)
I would create a temporary table in the memory, parse this string and insert into that table, then do a simple query with the condition where assetName in (select assetName from #tempTable)
I wrote about MSSQL 2000 because I am not sure whether MSSQL 2005 has some new data type like an array that can be passed as a literal to the SP.