I am trying to print SQL result through python code, where I an trying to pass different predicates of the where clause from a for loop. But the code only taking the last value from the loop and giving the result.
In the below example I have two distinct id values 'aaa' and 'bbb'. There are 4 records for id value = 'aaa' and 2 records for the id value = 'bbb'.
But the below code only giving me the result for the id value ='bbb' not for id value 'aaa'
Can anyone help to identify what exactly wrong I am doing?
import pymysql
db = pymysql.connect(host="localhost", user="user1", passwd="pass1", db="db1")
cur = db.cursor()
in_lst=['aaa', 'bbb']
for i in in_lst:
Sql = "SELECT id, val, typ FROM test123 Where id='{inpt}'".format(inpt=i)
print(Sql)
cur.execute(Sql)
records = cur.fetchall()
print(records)
db.close()
The result I am getting as below
C:\Python34\python.exe C:/Users/Koushik/PycharmProjects/Test20161204/20170405.py
SELECT id, val, typ FROM test123 Where id='bbb'
(('bbb', 5, '1a'), ('bbb', 17, '1d'))
Process finished with exit code 0
import pymysql
db = pymysql.connect(host="localhost", user="root", passwd="1234", db="sakila")
cur = db.cursor()
in_lst=['1', '2']
for i in in_lst:
Sql = "SELECT * FROM actor Where actor_id='{inpt}'".format(inpt=i)
print(Sql)
cur.execute(Sql)
records = cur.fetchall()
print(records)
db.close()
Indentation is your problem, please update the code according to your needs...
Within your for loop, you're formatting the sql statement to replace "{inpt}" with "aaa". However, before you do anything with that value, you're immediately overwriting it with the "bbb" version.
You would need to either:
Store the results somehow before the next iteration of the loop, then process them outside of the loop.
Process the results within the loop.
Something like the following will give you a list containing both results from the fetchall() calls:
import pymysql
db = pymysql.connect(host="localhost", user="user1", passwd="pass1", db="db1")
cur = db.cursor()
in_lst=['aaa', 'bbb']
records = list()
for i in in_lst:
Sql = "SELECT id, val, typ FROM test123 Where id='{inpt}'".format(inpt=i)
print(Sql)
cur.execute(Sql)
records.append(cur.fetchall())
print(records)
db.close()
Related
in my python code I insert a value into a table.
In the table, there is a sequence which automatically assigns an ID.
After the insert, I want to get this it back in to my python application:
import cx_Oracle, sys
with cx_Oracle.connect(user=ORA_USER,password=ORA_PWD,dsn=ORA_DSN) as conn:
with conn.cursor() as cur:
cur.execute("Insert into my_table columns(data) values ('Hello')")
conn.commit()
with cx_Oracle.connect(user=ORA_USER,password=ORA_PWD,dsn=ORA_DSN) as conn:
with conn.cursor() as cur:
r = cur.execute("select id from my_table where data = 'Hello'")
print(r)
if r is None:
print("Cannot retrieve ID")
sys.exit()
Unfortunately, the result set r is always "None" even though the value has been inserted properly (checked via sqldeveloper).
What am I doing wrong?
I even open a new connection to be sure to grab the value...
After calling execute() for a SELECT statement you need to call fetchone(), fetchmany() or fetchall() as shown in the cx_Oracle documentation SQL Queries.
Or you can use an iterator:
with connection.cursor() as cursor:
try:
sql = """select systimestamp from dual"""
for r in cursor.execute(sql):
print(r)
sql = """select 123 from dual"""
(c_id,) = cursor.execute(sql).fetchone()
print(c_id)
except oracledb.Error as e:
error, = e.args
print(sql)
print('*'.rjust(error.offset+1, ' '))
print(error.message)
However to get an automatically generated ID returned without the overhead of an additional SELECT, you can change the INSERT statement to use a RETURNING INTO clause. There is an example in the cx_Oracle documentation DML RETURNING Bind Variables that shows an UPDATE. You can use similar syntax with INSERT.
With the table:
CREATE TABLE mytable
(myid NUMBER(11) GENERATED BY DEFAULT ON NULL AS IDENTITY (START WITH 1),
mydata VARCHAR2(20));
You can insert and get the generated key like:
myidvar = cursor.var(int)
sql = "INSERT INTO mytable (mydata) VALUES ('abc') RETURNING myid INTO :bv"
cursor.execute(sql, bv=myidvar)
i, = myidvar.getvalue()
print(i)
If you just want a unique identifier you get the ROWID of an inserted row without needing a bind variable. Simple access cursor.lastrowid after executing an INSERT.
I have a SQL-file (SQLite format 3) that I can query with the DB Browser for SQLite (Windows). Whenever I use Python to access the db I get a Null result.
import sqlite3
conn = sqlite3.connect('C:/tmp/test.sql')
cursor = conn.cursor()
conn.execute('select count(*) from Player')
print("result is:", cursor.fetchone()) # result is: None
Every Select statement leads to "result is: None".
Any ideas?
Bart.
import sqlite3
connection = sqlite3.connect(database_name)
cursor = connection.cursor()
cursor.execute("select val from table_name where x = 'something';")
result = cursor.fetchone()
# directly returning result also gives null
if result:
return result[0] # tuple returned in result
cursor.close()
connection.close()
I'm trying to write a python script to get a count of some tables for monitoring which looks a bit like the code below. I'm trying to get an output such as below and have tried using python multi-dimensional arrays but not having any luck.
Expected Output:
('oltptransactions:', [(12L,)])
('oltpcases:', [(24L,)])
Script:
import psycopg2
# Connection with the DataBase
conn = psycopg2.connect(user = "appuser", database = "onedb", host = "192.168.1.1", port = "5432")
cursor = conn.cursor()
sql = """SELECT COUNT(id) FROM appuser.oltptransactions"""
sql2 = """SELECT count(id) FROM appuser.oltpcases"""
sqls = [sql,sql2]
for i in sqls:
cursor.execute(i)
result = cursor.fetchall()
print('Counts:',result)
conn.close()
Current output:
[root#pgenc python_scripts]# python multi_getrcount.py
('Counts:', [(12L,)])
('Counts:', [(24L,)])
Any help is appreciated.
Thanks!
I am a bit reluctant to show this way, because best practices recommend to never build a dynamic SQL string but always use a constant string and parameters, but this is one use case where computing the string is legit:
a table name cannot be a parameter in SQL
the input only comes from the program itself and is fully mastered
Possible code:
sql = """SELECT count(*) from appuser.{}"""
tables = ['oltptransactions', 'oltpcases']
for t in tables:
cursor.execute(sql.format(t))
result = cursor.fetchall()
print("('", t, "':,", result, ")")
I believe something as below, Unable to test code because of certificate issue.
sql = """SELECT 'oltptransactions', COUNT(id) FROM appuser.oltptransactions"""
sql2 = """SELECT 'oltpcases', COUNT(id) FROM appuser.oltpcases"""
sqls = [sql,sql2]
for i in sqls:
cursor.execute(i)
for name, count in cursor:
print ("")
Or
sql = """SELECT 'oltptransactions :'||COUNT(id) FROM appuser.oltptransactions"""
sql2 = """SELECT 'oltpcases :'||COUNT(id) FROM appuser.oltpcases"""
sqls = [sql,sql2]
for i in sqls:
cursor.execute(i)
result = cursor.fetchall()
print(result)
I am working with a SQL Database on Python. After making the connection, I want to use the output of one query in another query.
Example: query1 gives me a list of all tables in a schema. I want to use each table name from query1 in my query2.
query2 = "SELECT TOP 200 * FROM db.schema.table ORDER BY ID"
I want to use this query for each of the table in the output of query1.
Can someone help me with the Python code for it?
Here is a working example on how to do what you are looking to do. I didn't look up the schemes for the tablelist, but you can simply substitute the SQL code to do so. I just 'faked it' by unioning a statement of 2 tables. There are plenty of other answer on that SQL code and I don't want to clutter this answer:
How do I get list of all tables in a database using TSQL?
It looks like the key part you may have been missing was the join step to build the second SQL statement. This should be enough of a starting point to craft exactly what you are looking for.
import pypyodbc
def main():
table_list = get_table_list()
for table in table_list:
print_table(table)
def print_table(table):
thesql = " ".join(["SELECT TOP 10 businessentityid FROM", table])
connection = get_connection()
cursor = connection.cursor()
cursor.execute(thesql)
for row in cursor:
print (row["businessentityid"])
cursor.close()
connection.close()
def get_table_list():
table_list = []
thesql = ("""
SELECT 'Sales.SalesPerson' AS thetable
UNION
SELECT 'Person.BusinessEntity' thetable
""")
connection = get_connection()
cursor = connection.cursor()
cursor.execute(thesql)
for row in cursor:
table_list.append(row["thetable"])
cursor.close()
connection.close()
return table_list
def get_connection():
'''setup connection depending on which db we are going to write to in which environment'''
connection = pypyodbc.connect(
"Driver={SQL Server};"
"Server=YOURSERVER;"
"Database=AdventureWorks2014;"
"Trusted_Connection=yes"
)
return connection
main ()
I have this great pyodbc lib. I try the code below, it supposed to insert a row and return the row id but it didn't work. by the way I'm using sql server 2005 on server and client is windows os
...
con = pyodbc.connect('conectionString', autocommit = True)
cur = con.execute(
"insert into sometable values('something');
select scope_identity() as id"
)
for id in cur:
print id
...
some idea?
Try this, one statement with the OUTPUT clause
cur = con.execute(
"insert into sometable OUTPUT INSERTED.idcolumn values('something')"
)
row = cur.fetchone()
lastrowid = row[0]
Edit: This should get around the issue commented by Joe S.
Using SCOPE_IDENTITY() is the way to go as there are limitations and quirks using OUTPUT and ##IDENTITY because of triggers.
Using your code snipped, you just need to add a call to nextset to get the id.
...
con = pyodbc.connect('conectionString', autocommit = True)
cur = con.execute(
"insert into sometable values('something');
select scope_identity() as id"
)
cur.nextset()
for id in cur:
print id
...