I'm trying to use the results from one query to use in the where clause of another and cannot get it to work. at the moment i'm getting an error....
ProgrammingError: ibm_db_dbi::ProgrammingError: Exception('Statement Execute Failed: [IBM][CLI Driver] CLI0100E Wrong number of parameters. SQLSTATE=07001 SQLCODE=-99999')
My code below (eventually, 'result' will just be a variable assigned to the results from another query, but for now i'm just trying to get it to work with a static variable. Thanks in advance!
import ibm_db_dbi as db
result = ['c80fS4Pn1', '9f*hzNT21']
conn = db.connect('DRIVER=DB2 zOS;'
'DATABASE=xxxx;'
'HOSTNAME=xxxx.com;'
'PORT=xxx;'
'PROTOCOL=xxxx;'
'UID=id;'
'PWD=passord;', '', '')
cur = conn.cursor()
sql = "SELECT * FROM SCHEMA.TABLE WHERE PRIM_KEY IN (?)"
cur.execute(sql, (result))
conn.close()
The reason you get error CLI0100E is because in your code-sample you show a list (called result) with two entries, while in your query there is a single parameter-marker (?)
The number of parameters to be bound (as done by the cur.execute()), must exactly match the number of parameter-markers in the query
As you usually do not know in advance the number of rows returned from a query, you usually don't know the number of parameter-markers in advance.
You could dynamically generate the number of parameter markers to match the number of rows in the previous result-set. Or you could generate the SQL string in full without parameter markers which is inefficient and might not scale.
It is wise to do in SQL the things that SQL is good at doing, such as passing the results of a sub-query into another query. Trying to do that in client side code (instead of inside the SQL engine) may be inelegant and slow.
Related
This code:
cursor.execute('select RLAMBD from ?', OPTable)
print cursor.fetchone().RLAMBD
produces this error:
ProgrammingError: ('42S02', '[42S02] [Oracle][ODBC][Ora]ORA-00903: invalid table name\n (903) (SQLExecDirectW)')
OPTable is an alphanumeric string which I've built from another database query which contains the table name I want to select from.
The following code works just fine within the same script.
sql = 'select RLAMBD from ' + OPTable
cursor.execute(sql)
print cursor.fetchone().RLAMBD
I guess it's not a huge deal to build the sql statements this way, but I just don't understand why it's not accepting the ? parameters. I even have another query in the same script which uses the ? parameterization and works just fine. The parameters for the working query are produced using the raw_input function, though. Is there some subtle difference between the way those two strings might be formatted that's preventing me from getting the query to work? Thank you all.
I'm running python 2.7 and pyodbc 3.0.10.
Parameter placeholders cannot be used to represent object names (e.g., table or column names) or SQL keywords. They are only used to pass data values, e.g., numbers, strings, dates, etc..
I am retrieving some data from sql server and trying to write it to a text file, I am getting error in retrieving and passing it to variable Could you please help me in this.
You don't give a lot of detail regarding the error. Assuming your query is working and returning data to the table, Streamwriter.Write(dt) won't return the data in the table, it will return the name of the table or something like that. to get all the data you need to either loop through the rows and columns and print each one as you like or use dt.WriteXML(myIOStream), obWRiter.(myIOstream). You can also try streamwriter.write(dt.writexml()). I haven't tried anything out so you'll need to work on the code.
As I've just start learning to use sqlalchemy recently, the result of the following code make me confused about when sqlalchemy execute the query:
query = db.session.query(MyTable)
query = query.filter(...)
query = query.limit(...)
query = query.offset(...)
records = query #records=query.all()
for r in records:
#do something
note the line
records = query #records=query.all()
Seems that it brings the same correct result(stored in variable "records") when using "query" and "query.all()", I wonder when was the query executed?
If it is executed during the first line "db.session.query(MyTable)", the result set may be large at this point; if during the fifth line "records = query", how could that happen as there's no function call at all?
In your example, the query gets executed upon for r in records. Accessing the query object via iterator triggers the execution. (Normally, only then will it be compiled into a SELECT statement)
Up until this time, the query will be built (via filter, limit etc).
Please read also the ORM Tutorial on querying
My project is in Visual Foxpro and I use MS SQL server 2008. When I fire sql queries in batch, some of the queries don't execute. However, no error is thrown. I haven't used BEGIN TRAN and ROLLBACK yet. What should be done ??
that all depends... You don't have any sample of your queries posted to give us an indication of possible failure. However, one thing I've had good response with from VFP to SQL is to build into a string (I prefer using TEXT/ENDTEXT for readabilty), then send that entire value to SQL. If there are any "parameter" based values that are from VFP locally, you can use "?" to indicate it will come from a variable to SQL. Then you can batch all in a single vs multiple individual queries...
vfpField = 28
vfpString = 'Smith'
text to lcSqlCmd noshow
select
YT.blah,
YT.blah2
into
#tempSqlResult
from
yourTable YT
where
YT.SomeKey = ?vfpField
select
ost.Xblah,
t.blah,
t.blah2
from
OtherSQLTable ost
join #tempSqlResult t
on ost.Xblah = t.blahKey;
drop table #tempSqlResult;
endtext
nHandle = sqlconnect( "your connection string" )
nAns = sqlexec( nHandle, lcSqlCmd, "LocalVFPCursorName" )
No I don't have error trapping in here, just to show principle and readability. I know the sample query could have easily been done via a join, but if you are working with some pre-aggregations and want to put them into temp work areas like Localized VFP cursors from a query to be used as your next step, this would work via #tempSqlResult as "#" indicates temporary table on SQL for whatever the current connection handle is.
If you want to return MULTIPLE RESULT SETs from a single SQL call, you can do that too, just add another query that doesn't have an "into #tmpSQLblah" context. Then, all instances of those result cursors will be brought back down to VFP based on the "LocalVFPCursorName" prefix. If you are returning 3 result sets, then VFP will have 3 cursors open called
LocalVFPCursorName
LocalVFPCursorName1
LocalVFPCursorName2
and will be based on the sequence of the queries in the SqlExec() call. But if you can provide more on what you ARE trying to do and their samples, we can offer more specific help too.
On trying to use a select query statement. The input variable has 8 characters just as expected.
I dont know why this error comes for select query because for a select query it will query and if its available it will return else it will retun blank rows.
Hibernate is used. Even in mapping its correctly mapped as 8 only.
This is what i found in log file:
Cause = com.ibm.db2.jcc.a.SqlException: The value of a host variable in the EXECUTE or OPEN statement is too large for its corresponding use.
Has anybody come across this error before? Please suggest me some solutions on why this error occurs..
One possibility... This issue can come even in SELECT statement. When the parameter passed into the query is more than the size of its datatype's size, this error will pop-up.
Example:
Datatype - CHAR(12)
Search Param: "123456789012345"