I have an issue when displaying a value in python retrieved from oracle table into CLOB field:
Oracle query:
SELECT EXTRACTVALUE(xmltype(t.xml), '/DCResponse/ResponseInfo/ApplicationId')
FROM table t
WHERE id = 2
Value displayed in Oracle Client
5701200
Python code
import cx_Oracle
conn = cx_Oracle.Connection("user/pwd#localhost:1521/orcl")
cursor = conn.cursor()
cursor.execute("""SELECT EXTRACTVALUE(xmltype(t.xml),'/DCResponse/ResponseInfo/ApplicationId') FROM table t where id = 2""")
for row in cursor:
print(row)
Python Console: Nothing is displayed!!! I want to show:5701200
Please Help.
Best Regards
Giancarlo
There are only a few issues with your code :
Replace cx_Oracle.Connection with cx_Oracle.connect
Be careful about the indentation related to the print(row)
Triple double-quotes, within the SELECT statement, are redundant,
replace them with Single double-quotes
Prefer Using print(row[0]) in order to return the desired number rather than
a tuple printed.
import cx_Oracle
conn = cx_Oracle.connect('user/pwd#localhost:1521/orcl')
cursor = conn.cursor()
query = "SELECT EXTRACTVALUE(xmltype(t.xml),'/DCResponse/ResponseInfo/ApplicationId')"
query += " FROM tab t "
query += " WHERE t.ID = 2 "
cursor.execute( query )
for row in cursor:
print(row[0])
Assigning a query to a variable not required, as stated in my case, but preferable to use in order to display the long SELECT statement decently.
If you want to iterate over result, use this one:
for row in cursor.execute("sql_query")
print(row)
or you can fetch each row like this:
cursor = conn.cursor()
cursor.execute("sql_query")
while True:
row = cursor.fetchone()
print(row)
Related
I have a doubt about python and sqlite3.
import sqlite3
conna= sqlite3.connect('db_a')
a = conna.cursor()
connb= sqlite3.connect('db_b')
b = conna.cursor()
I don't know how to ask the relational question between banks, can someone instruct me?
I don't want to use DEF, just the SELECT code for a variable to assume
query = """SELECT COL1 FROM TABLE1.DB_A WHERE NOT EXISTS (SELECT COL1 FROM TABLE2.DB_B WHERE COL1.TABLE2.DE_B = COL1.TABLE1.DE_A)"""
cursor.execute(query)
records = cursor.fetchall()
for row in records:
print(row[0])
Can someone help me?
If the tables exist in different databases you need the ATTACH DATABASE statement to use the 2nd database with the connection object that you connect to the 1st database:
import sqlite3
conn = sqlite3.connect('db_a')
cursor = conn.cursor()
attach = "ATTACH DATABASE 'db_b' AS db_b;"
cursor.execute(attach)
query = """
SELECT t1.COL1
FROM TABLE1 AS t1
WHERE NOT EXISTS (
SELECT t2.COL1
FROM db_b.TABLE2 AS t2
WHERE t2.COL1 = t1.COL1
)
"""
cursor.execute(query)
records = cursor.fetchall()
for row in records:
print(row[0])
detach = "DETACH DATABASE db_b;"
cursor.execute(detach)
Also, instead of EXISTS you could use EXCEPT with the difference being that EXCEPT returns only distinct results:
query = """
SELECT COL1 FROM TABLE1
EXCEPT
SELECT COL1 FROM db_b.TABLE2
"""
I'm aware that the best way to prevent sql injection is to write Python queries of this form (or similar):
query = 'SELECT %s %s from TABLE'
fields = ['ID', 'NAME']
cur.execute(query, fields)
The above will work for a single query, but what if we want to do a UNION of 2 SQL commands? I've set this up via sqlite3 for sake of repeatability, though technically I'm using pymysql. Looks as follows:
import sqlite3
conn = sqlite3.connect('dummy.db')
cur = conn.cursor()
query = 'CREATE TABLE DUMMY(ID int AUTO INCREMENT, VALUE varchar(255))'
query2 = 'CREATE TABLE DUMMy2(ID int AUTO INCREMENT, VALUE varchar(255)'
try:
cur.execute(query)
cur.execute(query2)
except:
print('Already made table!')
tnames = ['DUMMY1', 'DUMMY2']
sqlcmds = []
for i in range(0,2):
query = 'SELECT %s FROM {}'.format(tnames[i])
sqlcmds.append(query)
fields = ['VALUE', 'VALUE']
sqlcmd = ' UNION '.join(sqlcmds)
cur.execute(sqlcmd, valid_fields)
When I run this, I get a sqlite Operational Error:
sqlite3.OperationalError: near "%": syntax error
I've validated the query prints as expected with this output:
INSERT INTO DUMMY VALUES(%s) UNION INSERT INTO DUMMY VALUES(%s)
All looks good there. What is the issue with the string substitutions here? I can confirm that running a query with direct string substitution works fine. I've tried it with both selects and inserts.
EDIT: I'm aware there are multiple ways to do this with executemany and a few other. I need to do this with UNION for the purposes I'm using this for because this is a very, very simplified example fo the operational code I'm using
The code below executes few INSERTS at once
import sqlite3
conn = sqlite3.connect('dummy.db')
cur = conn.cursor()
query = 'CREATE TABLE DUMMY(ID int AUTO INCREMENT NOT NULL, VALUE varchar(255))'
try:
cur.execute(query)
except:
print('Already made table!')
valid_fields = [('ya dummy',), ('stupid test example',)]
cur.executemany('INSERT INTO DUMMY (VALUE) VALUES (?)',valid_fields)
firstly apologies for the basic question, just starting off with Python.
I have the following code:
import sqlite3
conn = sqlite3.connect("test.sqb")
cursor = conn.cursor()
sql = "SELECT * FROM report WHERE type LIKE 'C%'"
cursor.execute(sql)
data = cursor.fetchall()
for row in data:
print (row[0])
cursor.execute("UPDATE report SET route='ABCDE'")
conn.commit()
conn.close()
Why is it updating all records and not just the filtered records from sql query, even though the print (row[0]) just shows the filtered records.
Many thanks.
What's actually happening is you are running this query for each record returned from the SELECT query.
UPDATE report SET route='ABCDE'
If you only want to update route where type starts with C add the criteria to the UPDATE query and execute it once.
import sqlite3
conn = sqlite3.connect("test.sqb")
cursor = conn.cursor()
sql = "SELECT * FROM report WHERE type LIKE 'C%'"
cursor.execute(sql)
data = cursor.fetchall()
cursor.execute("UPDATE report SET route='ABCDE' WHERE type LIKE 'C%'")
conn.commit()
conn.close()
First of all I am trying to retrieve a list of all possible databases, that works fine.
In the second part it executes a query for each database in the list. And it will give me back the name and create_Date for each database where the create_Date is equal or greater than 01-01-2020.
So when I when do 'print(row)' it gives me exaclty what I want.
But how do I write the result of the query to an Excel file? I already import pandas as pd.
cnxn = pyodbc.connect('DRIVER={ODBC Driver 17 for SQL Server};'f'Server={server};'f'Database=
{db};'f'UID={username};'f'PWD={password};')
cursor = cnxn.cursor()
cursor.execute("SELECT name FROM master.dbo.sysdatabases")
result = cursor.fetchall()
ams_sql02 = []
for row in result:
ams_sql02.append(row[0])
ams_sql02 = [databases.lower() for databases in ams_sql02]
cursor = cnxn.cursor()
for db in ams_sql02:
cursor.execute(f'SELECT name, convert(varchar(10),create_date,103) as dateCreated fROM
sys.databases where name = \'{db}\' and create_date > \'2020-01-01 10:13:03.290\'
order by create_date')
result = cursor.fetchall()
for row in result:
print(row)
Why not put SQL query to Excel without Python? Excel works with datasources like MS SQL Server quite well.
I have a MySQL Table named TBLTEST with two columns ID and qSQL. Each qSQL has SQL queries in it.
I have another table FACTRESTTBL.
There are 10 rows in the table TBLTEST.
For example, On TBLTEST lets take id =4 and qSQL ="select id, city, state from ABC".
How can I insert into the FACTRESTTBL from TBLTEST using python, may be using dictionary?
Thx!
You can use MySQLdb for Python.
Sample code (you'll need to debug it as I have no way of running it here):
#!/usr/bin/python
import MySQLdb
# Open database connection
db = MySQLdb.connect("localhost","testuser","test123","TESTDB" )
# prepare a cursor object using cursor() method
cursor = db.cursor()
# Select qSQL with id=4.
cursor.execute("SELECT qSQL FROM TBLTEST WHERE id = 4")
# Fetch a single row using fetchone() method.
results = cursor.fetchone()
qSQL = results[0]
cursor.execute(qSQL)
# Fetch all the rows in a list of lists.
qSQLresults = cursor.fetchall()
for row in qSQLresults:
id = row[0]
city = row[1]
#SQL query to INSERT a record into the table FACTRESTTBL.
cursor.execute('''INSERT into FACTRESTTBL (id, city)
values (%s, %s)''',
(id, city))
# Commit your changes in the database
db.commit()
# disconnect from server
db.close()