Develop Reference

Error executing cursor.execute when quotes are required

fairly new to SQL in general. I'm currently trying to bolster my general understanding of how to pass commands via cursor.execute(). I'm currently trying to grab a column from a table and rename it to something different.
import mysql.connector
user = 'root'
pw = 'test!*'
host = 'localhost'
db = 'test1'
conn = mysql.connector.connect(user=user, password=pw, host=host, database=db)
cursor = conn.cursor(prepared=True)
new_name = 'Company Name'
query = f'SELECT company_name AS {new_name} from company_directory'
cursor.execute(query)
fetch = cursor.fetchall()
I've also tried it like this:
query = 'SELECT company_name AS %s from company_directory'
cursor.execute(query, ('Company Name'),)
fetch = cursor.fetchall()
but that returns the following error:
stmt = self._cmysql.stmt_prepare(statement)
_mysql_connector.MySQLInterfaceError: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '? from company_directory' at line 1
I'm using python and mySQL. I keep reading about database injection and not using string concatenation but every time I try to use %s I get an error similar to the one below where. I've tried switching to ? syntax but i get the same error.
If someone could ELI5 what the difference is and what exactly database injection is and if what I'm doing in the first attempt qualifies as string concatenation that I should be trying to avoid.
Thank you so much!

If a column name or alias contains spaces, you need to put it in backticks.
query = f'SELECT company_name AS `{new_name}` from company_directory'
You can't use a placeholder for identifiers like table and column names or aliases, only where expressions are allowed.

You can't make a query parameter in place of a column alias. The rules for column aliases are the same as column identifiers, and they must be fixed in the query before you pass the query string.
So you could do this:
query = f"SELECT company_name AS `{'Company Name'}` from company_directory'
cursor.execute(query)

SQL compilation error-- Snowsql validation using python

I am following this tutorial :https://docs.snowflake.com/en/sql-reference/functions/validate.html
to try and 'return errors by query ID and saves the results to a table for future reference'
however for a seamless transfer I don't want to be putting the job id always as it would require me to go to snowflake console- go to history- get the jobid -copy and paste it to python code.
Instead I wanted to go with just the tablename which is a variable and 'last_query_id()' and give me the list errors. Is there any way i can achieve this?
import snowflake.connector
tableName='F58155'
ctx = snowflake.connector.connect(
user='*',
password='*',
account='*')
cs = ctx.cursor()
ctx.cursor().execute("USE DATABASE STORE_PROFILE_LANDING")
ctx.cursor().execute("USE SCHEMA PUBLIC")
try:
ctx.cursor().execute("PUT file:///temp/data/{tableName}/* #%
{tableName}".format(tableName=tableName))
except Exception:
pass
ctx.cursor().execute("truncate table {tableName}".format(tableName=tableName))
ctx.cursor().execute("COPY INTO {tableName} ON_ERROR = 'CONTINUE' ".format(tableName=tableName,
FIELD_OPTIONALLY_ENCLOSED_BY = '""', sometimes=',', ERROR_ON_COLUMN_COUNT_MISMATCH = 'TRUE'))
I have tried the below validate function....it is giving me error on this line
the error is "SQL compilation error:
syntax error line 1 at position 74 unexpected 'tableName'.
syntax error line 1 at position 83 unexpected '}'."
ctx.cursor().execute("create or replace table save_copy_errors as select * from
table(validate({tableName},'select last_query_id()'))");
ctx.close()

The line
ctx.cursor().execute("create or replace table save_copy_errors as select * from
table(validate({tableName},'select last_query_id()'))");
should be replaced with these two
job_id = ctx.cursor().execute("select last_query_id()").fetchone()[0]
ctx.cursor().execute(f"create or replace table save_copy_errors as select * from
table(validate({tableName},job_id=>'{job_id}'))");

Dremio ODBC with Python

Getting below error while running this code in Python, If anyone could advise me on this that would be appreciated. Thanks
dataframe = pandas.read_sql(sql,cnxn)
DatabaseError: Execution failed on sql 'SELECT * FROM train_data': ('HY000', "[HY000] [Dremio][Connector] (1040) Dremio failed to execute the query: SELECT * FROM train_data\n[30038]Query execution error. Details:[ \nVALIDATION ERROR: Table 'train_data' not found\n\nSQL Query SELECT * FROM train_data\nstartLine 1\nstartColumn 15\nendLine 1\nendColumn 24\n\n[Error Id: 24c7de0e-6e23-44c6-8cb6-b0a110bbd2fd on user:31010]\n\n (org.apache.calcite.runtime.CalciteContextException) From line 1, column 15 to line 1, column 24: ...[see log] (1040) (SQLExecDirectW)")

You only need to provide your Space name, just before your table name.
for example:
SELECT * FROM
SpaceName.train_data
This is a query to fetch data from Dremio Space, Dremio source cannot be used for data ingestion. Dremio Source only be used to establish a connection between database and Dremio.

this is being solved, it says that table does not exist, should give a valid table, in dremio it can be inside a specific space

MySQL update with multiple variable in set

Well, I have a dictionary as input, ex:{'date':2020}.
And the key is the column name of the table, I just wanted to update the value into the table
string = ["{} = '{}'".format(k,v) for k,v in parameter_dict.items()]
string_joined =", ".join(string)
query = "UPDATE experiment SET" + string_joined + ' ' + 'WHERE ID =' + str(experimentID)
cursor.execute(query)
Above code causes error
_mysql.connector.errors.ProgrammingError: 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '= 'Mar-2020-16_25_18', training_minutes = '0' WHERE ID =21' at line 1
"UPDATE experiment SET %s WHERE ID =%s", (string_joined, experimentID)
Using above statement causes same error too
mysql.connector.errors.ProgrammingError: 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''date_end = \'Mar-2020-16_18_52\', training_minutes = \'0\'' WHERE ID = 20' at line 1
Also tried putting a single update into a for loop, but that causes another error!
So How can I solve this? Does it really can't send variables into the SET partition ? Thanks

Fail to run 'execute(sqlcmd)' of sqlite3 using Python,Ubuntu

I want to use sqlite3 to deal with data in Ubuntu with python. But I always failed and get errors. Codes related to database are as follows:
sqlite = "%s.db" % name
#connnect to the database
conn = sqlite3.connect(sqlite)
print "Opened database successfully"
c = conn.cursor()
#set default separator to "\t" in database
c.execute(".separator "\t"")
print "Set separator of database successfully"
#create table data_node
c.execute('''create table data_node(Time int,Node Text,CurSize int,SizeVar int,VarRate real,Evil int);''')
print "Table data_node created successfully"
node_info = "%s%s.txt" % (name,'-PIT-node')
c.execute(".import %\"s\" data_node") % node_info
print "Import to data_node successfully"
#create table data_face
data_info = "%s%s.txt" % (name,'-PIT-face')
c.execute('''create table data_face(Time int,Node Text,TotalEntry real,FaceId int,FaceEntry real,Evil int);''')
c.execute(".import \"%s\" data_face") % face_info
#get the final table : PIT_node
c.execute('''create table node_temp as select FIRST.Time,FIRST.Node,ROUND(FIRST.PacketsRaw/SECOND.PacketsRaw,4) as SatisRatio from tracer_temp FIRST,tracer_temp SECOND WHERE FIRST.Time=SECOND.Time AND FIRST.Node=SECOND.Node AND FIRST.Type='InData' AND SECOND.Type='OutInterests';''')
c.execute('''create table PIT_node as select A.Time,A.Node,B.SatisRatio,A.CurSize,A.SizeVar,A.VarRate,A.Evil from data_node A,node_temp B WHERE A.Time=B.Time AND A.Node=B.Node;''')
#get the final table : PIT_face
c.execute('''create table face_temp as select FIRST.Time,FIRST.Node,FIRST.FaceId,ROUND(FIRST.PacketsRaw/SECOND.PacketsRaw,4) as SatisRatio,SECOND.Packets from data_tracer FIRST,data_tracer SECOND WHERE FIRST.Time=SECOND.Time AND FIRST.Node=SECOND.Node AND FIRST.FaceId=SECOND.FaceId AND FIRST.Type='OutData' AND SECOND.Type='InInterests';''')
c.execute('''create table PIT_face as select A.Time,A.Node,A.FaceId,B.SatisRatio,B.Packets,ROUND(A.FaceEntry/A.TotalEntry,4),A.Evil from data_face as A,face_temp as B WHERE A.Time=B.Time AND A.Node=B.Node AND A.FaceId = B.FaceId;''')
conn.commit()
conn.close()
These sql-commands are right. When I run the code, it always shows sqlite3.OperationalError: near ".": syntax error. So how to change my code and are there other errors in other commands such as create table?

You have many problems in your code as posted, but the one you're asking about is:
c.execute(".separator "\t"")
This isn't valid Python syntax. But, even if you fix that, it's not valid SQL.
The "dot-commands" are special commands to the sqlite3 command line shell. It intercepts them and uses them to configure itself. They mean nothing to the actual database, and cannot be used from Python.
And most of them don't make any sense outside that shell anyway. For example, you're trying to set the column separator here. But the database doesn't return strings, it returns row objects—similar to lists. There is nowhere for a separator to be used. If you want to print the rows out with tab separators, you have to do that in your own print statements.
So, the simple fix is to remove all of those dot-commands.
However, there is a problem—at least one of those dot-commands actually does something:
c.execute(".import %\"s\" data_node") % node_info
You will have to replace that will valid calls to the library that do the same thing as the .import dot-command. Read what it does, and it should be easy to understand. (You basically want to open the file, parse the columns for each row, and do an executemany on an INSERT with the rows.)