I am a newbie to using query strings in mysql and I have tried to write this procedure to drop tables under certain conditions. I don't reall know what I'm doing wrong and need help with getting the procedure to work or for someone to point me in the right direction. Thanks.
BEGIN
DECLARE String scheduler = 'select status from mysql.scheduler where id=0' ;
DECLARE String auftragpos = 'SELECT count("SchemaName") FROM "SYS.Tables" where "SchemaName" = dwh and "Name" = lexware_fk_auftragpos';
DECLARE String auftrag = 'SELECT count("SchemaName") FROM "SYS.Tables" where "SchemaName" = dwh and "Name" = lexware_fk_auftrag';
IF(auftragpos > 1)
BEGIN
drop table "dwh.lexware_fk_auftragpos";
END
IF(auftrag > 1)
BEGIN
drop table "dwh.lexware_fk_auftrag";
END
END
The syntax for declaring a variable is
DECLARE variablename datatype;
So it should be
DECLARE auftragpos INT;
Then you need to assign the result of the query to the variable. You do that by putting the SELECT query in parentheses.
You also should not quote table names, and you need to quote the literal strings you're using for the schema and table names you're searching for.
SET auftragpos = (
SELECT count(*)
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = 'dwh' AND TABLE_NAME = 'lexware_fk_auftragpos');
But there's really no need to do this. If you want to prevent an error from DROP TABLE, just add the IF EXISTS option.
DROP TABLE IF EXISTS dwh.lexware_fk_auftragpos;
Related
I have made a stored procedure. I want it to filter the data by different parameters. If I pass one parameter, it should be filtered by one; if I pass two, it should be filtered by two, and so on, but it is not working.
Can anyone help me please?
DROP PROCEDURE IF EXISTS medatabase.SP_rptProvince2;
CREATE PROCEDURE medatabase.`SP_rptProvince2`(
IN e_Region VARCHAR(45)
)
BEGIN
DECLARE strQuery VARCHAR(1024);
DECLARE stmtp VARCHAR(1024);
SET #strQuery = CONCAT('SELECT * FROM alldata where 1=1');
IF e_region IS NOT NULL THEN
SET #strQuery = CONCAT(#strQuery, ' AND (regionName)'=e_Region);
END IF;
PREPARE stmtp FROM #strQuery;
EXECUTE stmtp;
END;
AFAIK, you can't have a variable argument list like that. You can do one of a couple of things:
Take a fixed maximum number of parameters, and check them for null-ness before concatenating:
CREATE PROCEDURE SP_rptProvince2(a1 VARCHAR(45), a2 VARCHAR(45), ...)
...
IF a1 IS NOT NULL THEN
SET #strQuery = CONCAT(#strQuery, ' AND ', a2);
END IF;
If you need predetermined fields to which the criteria in the argument apply (like the e_Region parameter in your existing code), then you modify the CONCAT operation appropriately.
Possible invocation:
CALL SP_rptProvince2('''North''', 'column3 = ''South''')
Take a single parameter that is much bigger than just 45 characters, and simply append it to the query (assuming it is not null).
Clearly, this places the onus on the user to provide the correct SQL code.
Possible invocation:
CALL SP_rptProvince2('RegionName = ''North'' AND column3 = ''South''')
There's not a lot to choose between the two. Either can be made to work; neither is entirely satisfactory.
You might note that there was a need to protect the strings in the arguments with extra quotes; that is the sort of thing that makes this problematic.
I found a JSON-based approach which works with the latest MySQL/MariaDB systems. Check the link below (Original Author is Federico Razzoli): https://federico-razzoli.com/variable-number-of-parameters-and-optional-parameters-in-mysql-mariadb-procedures
Basically, you take a BLOB parameter which is actually a JSON object and then do JSON_UNQUOTE(JSON_EXTRACT(json object, key)) as appropriate.
Lifted an extract here:
CREATE FUNCTION table_exists(params BLOB)
RETURNS BOOL
NOT DETERMINISTIC
READS SQL DATA
COMMENT '
Return whether a table exists.
Parameters must be passed in a JSON document:
* schema (optional). : Schema that could contain the table.
By default, the schema containing this procedure.
* table : Name of the table to check.
'
BEGIN
DECLARE v_table VARCHAR(64)
DEFAULT JSON_UNQUOTE(JSON_EXTRACT(params, '$.table'));
DECLARE v_schema VARCHAR(64)
DEFAULT JSON_UNQUOTE(JSON_EXTRACT(params, '$.schema'));
IF v_schema IS NULL THEN
RETURN EXISTS (
SELECT TABLE_NAME
FROM information_schema.TABLES
WHERE
TABLE_SCHEMA = SCHEMA()
AND TABLE_NAME = v_table
);
ELSE
RETURN EXISTS (
SELECT TABLE_NAME
FROM information_schema.TABLES
WHERE
TABLE_SCHEMA = v_schema
AND TABLE_NAME = v_table
);
END IF;
END;
I want the user to input whatever database they want to check and whatever tables they want to check. For example the call would look like this:
call tableCheck('MyDatabase', 'table1 table20 table3')
So the procedure would check for those tables (space delimited). I have my code down below but I am having problem checking the other tables, it reads the first but not the second or third one. SO my code is not looping or not reading the next word.
PROCEDURE `tableCheck` (db VARCHAR(256), db_tables VARCHAR(256))
BEGIN
DECLARE tbl, tbls VARCHAR(256);
DECLARE c INT DEFAULT 0;
SET tbls = db_tables;
WHILE c = 0 DO
#split word
SET tbl = SUBSTRING_INDEX(tbls," ",1);
#go to next string
SET tbls = SUBSTR(tbls,LENGTH(tbl)+1);
#check every table
SELECT table_name AS 'Table Name'
FROM INFORMATION_SCHEMA.TABLES
WHERE table_schema=db AND table_name=tbl;
IF tbls = 0 THEN
SET c = 1;
END IF;
END WHILE;
END
I have given this link out a few times today...so maybe it will work for you too.
Convert a delimited string to a list of values
Using the dbo.fnArray function from that link you should be able to join on the INFORMATION_SCHEMA.TABLES like this:
create procedure dbo.spCheckTable #db varchar(256), #tbls varchar(8000)
as
begin
select *
from INFORMATION_SCHEMA.TABLES i
inner join dbo.fnArray(#tbls, ' ') t on i.TABLE_NAME = t.arrValue
where i.TABLE_CATALOG = #db
end
Now its a stored procedure
Stored Proc Definition:
DECLARE dbName varchar(255);
DECLARE tableName varchar(255);
DECLARE fullPath varchar(255);
DECLARE conditions varchar(255);
SET dbName = idbname;
SET tableName = itablename;
SET fullPath = CONCAT("'",dbName,"'",'.',"'",tableName,"'");
SET checkExists = 0;
I am creating a stored proc where the dbname and tablename are dynamic, however I am stuck on the select aspect of this query.
I am trying to repalce the _test.user with values passed into the stored proc.
SELECT count(*) INTO checkExists FROM `_test`.`user` WHERE id = 1;
However this line throws an error
SELECT count(*) INTO checkExists FROM fullPath WHERE id = 1;
Error:
Procedure execution failed
1146 - Table 'dbname.fullpath' doesn't exist
I have also tried CONCAT() like this
set conditions = CONCAT('SELECT count(*) INTO ',checkExists, ' FROM ', fullPath, ' WHERE id=', 1);
However I can't figure out even how to use this in a select? Help is appreciated.
I like to do these modifications using replace(). Something like this:
replace(replace('SELECT count(*) INTO checkExists FROM `<dbname>`.`<tname>` WHERE id = 1',
'<tname>', v_tablename
), '<dbname>', v_databasename
)
You may also want to use v_fullpath somewhere. I'm not really sure what query you actually want to create.
I'm not sure why you have a variable called checkExists, when it seems to be the destination file. However, I would suggest that you prepend all your local variables with something to distinguish them from column names.
I have a stored procedure
create PROCEDURE [dbo].[SP]
(
#OrderList varchar(500)
)
AS
Begin
select *
from table
where id in ('+ #OrderList +')
Here I am passing orderlist....
When I execute like this
exec sp 'iss005,iss006'
I am not getting data
but when I hardcode in sp like this ...
select * from table where id in ('iss005','iss006')
then am getting data...
Thank you
Unfortunately it won't work that way. If you change your procedure to something like the following, this will work:
Create Procedure dbo.SP
#OrderList varchar(500)
AS
Declare #SQL VarChar(1000)
Select #SQL = 'SELECT * FROM table '
Select #SQL = #SQL + 'WHERE id in (' + #OrderList +')'
Exec ( #SQL)
GO
Looking more into your query, your ID's value varchar, so the procedure will fail as you'll still be getting :
WHERE id in (iss005,iss006)
when you want :
WHERE id in ('iss005','iss006')
You would need to either pass in the quote values, e.g. :
#OrderList = 'iss005','iss006'
Or work out some SQL to split the #OrderList by comma and use the QUOTENAME() function to add the quotes to the new variable.
I strongly recommend in this case the use of XML parameters, will give you a lot of flexibility.
Your XML might be something like
<ids>
<id>iss006</id>
<id>iss005</id>
</ids>
Your procedure should be something like this:
create PROCEDURE [dbo].[SP]
(
#OrderList XML
)
AS
Begin
select * from table
where id in (
select ParamValues.ID.value('.','VARCHAR(50)')
FROM #OrderList.nodes('/ids/id') as ParamValues(id)
)
Besides the use of store procedures outputs I also would recommend the use of functions but that is up to you.
Regards.
I had the same kind of requirement. i was getting list of user in a int list variable and i need to get all the order of those user. I have use a very simple trick which had solve my issue. please find the code.
public DataTable GetAllOrderData(List<int> UserID)
{
try
{
string listofuser = String.Join(",", UserID.ToArray());
SqlParameter[] parameters = new SqlParameter[]
{
new SqlParameter("#USERID", listofuser)
};
return SqlDBHelper.ExecuteParamerizedSelectCommand("GetOrderByUserID", System.Data.CommandType.StoredProcedure, parameters);
}
finally { UserID = null; }
}
And this is the stored procedure
CREATE PROCEDURE [dbo].[GetOrderByUserID] (#USERID varchar(700))
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
Declare #SQL VarChar(1000)
Select #SQL = 'SELECT *,ORM.OrganisationName FROM OrderTransaction ORT LEFT JOIN OrganisationMaster ORM ON (ORT.OrganisationID=ORM.OrganisationID) '
Select #SQL = #SQL + 'WHERE ORT.CreatedBy IN (' + #USERID +')'
Exec ( #SQL)
END
Is it possible to set a varaible to a query result such as:
DECLARE result INT;
SET result = (SELECT index FROM table WHERE data = 'xxxx' LIMIT 1);
Assuming of course you know that there will only be one result set
only within a procedure.