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2 questions: Importing data from MySQL data base to Python

Q1. My database contains 3 columns: time, value A and value B. The time data is written in the form 00:00:00 and the increment is 1 minute.
When I try to import data ...
cursor.execute (f"SELECT * FROM trffc_int_data.{i};")
instead getting (00:00:00, A, B), I get
(datetime.timedelta(0), 7, 2), (datetime.timedelta(seconds=60), 8, 5), .....
I suppose Python doesn't convert the time right. Any suggestions?
Q2. I have an initial database with the data mentioned above. I need to get the data from the initial database, convert it, and save it to another database.
I'm stuck at a point where data should be saved to a new table.
Here are the sections of the code...
# Creating new DB
NewDB = input(" :: Enter the Database name : ")
sqlsynt = f"CREATE DATABASE IF NOT EXISTS {NewDB}"
cursor.execute(sqlsynt,NewDB)
stdb.commit()
# Creating table and writing the data
cursor.execute (f"USE {NewDB}")
sqlsynt = f"CREATE TABLE {dayinweek} (time TIME, Vehicles INT(3), Pedestrians INT(3))"
cursor.execute (sqlsynt, NewDB, dayinweek)
#stdb.commit()
sqlsyntax = f"INSERT INTO {NewDB}.{dayinweek} (time, Vehicles, Pedestrians) VALUES (%s, %s, %s)"
cursor.executemany(sqlsyntax, temp_list_day)
The program stucks on the last line saying that there is no table 1 in NewDB!
mysql.connector.errors.ProgrammingError: 1146 (42S02): Table 'test001.1' doesn't exist
What's wrong with the code? Maybe the problem is in mixing f and %s formating?
Thanks in advance

If I am followin this correctly, you are creating a table called 1. Digit-only identifiers are not allowed in MySQL, unless the identifier is quoted, as explained in the documentation.
Identifiers may begin with a digit but unless quoted may not consist solely of digits.
Your create table statement did fail, but you did not notice that error until you tried to insert.
You could quote the table name, using backticks:
CREATE TABLE `{dayinweek}` (time TIME, Vehicles INT(3), Pedestrians INT(3))
And then:
INSERT INTO `{NewDB}`.`{dayinweek}` (time, Vehicles, Pedestrians) VALUES (%s, %s, %s)
Quoting the database name may also be a good idea: the same rules apply as for table names (and this is user input to start with).
But overall, changing the table name seems like a better option, as this makes for cleaner code: how about something like table1 for example - or better yet, a table name that is more expressive on what kind of data it contains, such as customer1, or sales1.
Note: your code is open to SQL injection, as you are passing user input directly to the database in a create database statement. Obviously such information cannot be parameterized, however I would still recommend performing a minimal sanity check on application side beforehand.

Too many server roundtrips w/ psycopg2

I am making a script, that should create a schema for each customer. I’m fetching all metadata from a database that defines how each customer’s schema should look like, and then create it. Everything is well defined, the types, names of tables, etc. A customer has many tables (fx, address, customers, contact, item, etc), and each table has the same metadata.
My procedure now:
get everything I need from the metadataDatabase.
In a for loop, create a table, and then Alter Table and add each metadata (This is done for each table).
Right now my script runs in about a minute for each customer, which I think is too slow. It has something to do with me having a loop, and in that loop, I’m altering each table.
I think that instead of me altering (which might be not so clever approach), I should do something like the following:
Note that this is just a stupid but valid example:
for table in tables:
con.execute("CREATE TABLE IF NOT EXISTS tester.%s (%s, %s);", (table, "last_seen date", "valid_from timestamp"))
But it gives me this error (it seems like it reads the table name as a string in a string..):
psycopg2.errors.SyntaxError: syntax error at or near "'billing'"
LINE 1: CREATE TABLE IF NOT EXISTS tester.'billing' ('last_seen da...

Consider creating tables with a serial type (i.e., autonumber) ID field and then use alter table for all other fields by using a combination of sql.Identifier for identifiers (schema names, table names, column names, function names, etc.) and regular format for data types which are not literals in SQL statement.
from psycopg2 import sql
# CREATE TABLE
query = """CREATE TABLE IF NOT EXISTS {shm}.{tbl} (ID serial)"""
cur.execute(sql.SQL(query).format(shm = sql.Identifier("tester"),
tbl = sql.Identifier("table")))
# ALTER TABLE
items = [("last_seen", "date"), ("valid_from", "timestamp")]
query = """ALTER TABLE {shm}.{tbl} ADD COLUMN {col} {typ}"""
for item in items:
# KEEP IDENTIFIER PLACEHOLDERS
final_query = query.format(shm="{shm}", tbl="{tbl}", col="{col}", typ=i[1])
cur.execute(sql.SQL(final_query).format(shm = sql.Identifier("tester"),
tbl = sql.Identifier("table"),
col = sql.Identifier(item[0]))
Alternatively, use str.join with list comprehension for one CREATE TABLE:
query = """CREATE TABLE IF NOT EXISTS {shm}.{tbl} (
"id" serial,
{vals}
)"""
items = [("last_seen", "date"), ("valid_from", "timestamp")]
val = ",\n ".join(["{{}} {typ}".format(typ=i[1]) for i in items])
# KEEP IDENTIFIER PLACEHOLDERS
pre_query = query.format(shm="{shm}", tbl="{tbl}", vals=val)
final_query = sql.SQL(pre_query).format(*[sql.Identifier(i[0]) for i in items],
shm = sql.Identifier("tester"),
tbl = sql.Identifier("table"))
cur.execute(final_query)
SQL (sent to database)
CREATE TABLE IF NOT EXISTS "tester"."table" (
"id" serial,
"last_seen" date,
"valid_from" timestamp
)

However, this becomes heavy as there are too many server roundtrips.
How many tables with how many columns are you creating that this is slow? Could you ssh to a machine closer to your server and run the python there?
I don't get that error. Rather, I get an SQL syntax error. A values list is for conveying data. But ALTER TABLE is not about data, it is about metadata. You can't use a values list there. You need the names of the columns and types in double quotes (or no quotes) rather than single quotes. And you can't have a comma between name and type. And you can't have parentheses around each pair. And each pair needs to be introduced with "ADD", you can't have it just once. You are using the wrong tool for the job. execute_batch is almost the right tool, except it will use single quotes rather than double quotes around the identifiers. Perhaps you could add a flag to it tell it to use quote_ident.
Not only is execute_values the wrong tool for the job, but I think python in general might be as well. Why not just load from a .sql file?

How can I search a record in MySQL using Python

def search(title="",author="",year="",isbn=""):
con = mysql.connector.connect(host="localhost", user="root", passwd="junai2104", database="book")
cur = con.cursor()
sql_statement = "SELECT * FROM book WHERE title={} or author={} or year={} or isbn={} ".format(title,author,year,isbn)
cur.execute(sql_statement)
rows=cur.fetchall()
con.close()
return rows
print(search(title='test2'))
How can I search a value in MySQL using Python argument?
how to get a values from the argument?

You have a couple of issues with your code:
In your SQL SELECT statement you are looking for values in text columns (TEXT, VARCHAR etc.). To do so you must add single quotes to your search qriteria, since you want to indicate a text literal. So WHERE title={} should be WHERE title='{}' (same goes for the other parameters).
When one or more of your arguments are empty, you will search for rows where the respective value is an empty text. So in your example search(title='test2') will trigger a search for an entry where the title column has the value 'test2' or any of the other three columns (author, year and isbn) has an empty text. If you inted to look for a title 'test2', this will only work if none of the other columns will ever contain an empty text. And even then, because of the three OR operators in your query, performance will be poor. What you should do instead is to evaluate each parameter individually and construct the query only with the parameters that are not empty.
By constructing your query with formatting a string, you will create a massive security issue in case the values of your search parameters come from user input. Your code is wide open for SQL injection, which is one of the simplest and most effective attacks on your system. You should always parametrize your queries to prevent this attack. By general principle, never create SQL queries by formating or concatenating strings with their parameters. Note that with parametrized queries you do not need to add single quotes to your query as wriitten in point 1.

Python mysql using variable to select a certain field

Having a little tricky issue with python and mysql. To keep it simple, the following code returns whatever is in the variable 'field', which is a string. Such as 'username' or 'password'.
options = [field, userID]
entries = cursor.execute('select (?) from users where id=(?)', options).fetchall()
print(entries);
This code works correctly if I remove the first (?) and just use the actually name (like 'username') instead. Can anyone provide some input?

Your query is actually formed as:
select "field" from users where id="value"
which returns you a string "field" instead of the actual table field value.
You cannot parameterize column and table names (docs):
Parameter placeholders can only be used to insert column values. They
can not be used for other parts of SQL, such as table names,
statements, etc.
Use string formatting for that part:
options = [userID]
query = 'select {field} from users where id=(?)'.format(field=field)
cursor.execute(query, options).fetchall()
Related threads with some more explanations:
pysqlite: Placeholder substitution for column or table names?
Python MySQLdb: Query parameters as a named dictionary

dynamic table mysqldb python string/int issue

I am receiving an error when trying to write data to a database table when using a variable for the table name that I do not get when using a static name. For some reason on the line where I insert, if I insert an integer as the column values the code runs and the table is filled, however, if I try to use a string I get a SQL syntax error
cursor = db.cursor()
cursor.execute('DROP TABLE IF EXISTS %s' %data[1])
sql ="""CREATE TABLE %s (IP TEXT, AVAILIBILITY INT)""" %data[1]
cursor.execute(sql)
for key in data[0]:
cur_ip = key.split(".")[3]
cursor.execute("""INSERT INTO %s VALUES (%s,%s)""" %(data[1],key,data[0][key]))
db.commit()
the problem is where I have %(data[1], key, data[0][key]) any ideas?

It's a little hard to analyse your problem when you don't post the actual error, and since we have to guess what your data actually is. But some general points as advise:
Using a dynamic table name is often not way DB-systems want to be used. Try thinking if the problem could be used by using a static table name and adding an additional key column to your table. Into that field you can put what you did now as a dynamic table name. This way the DB might be able to better optimize your queries, and your queries are less likely to get errors (no need to create extra tables on the fly for once, which is not a cheap thing to do. Also you would not have a need for dynamic DROP TABLE queries, which could be a security risk.
So my advice to solve your problem would be to actually work around it by trying to get rid of dynamic table names altogether.
Another problem you have is that you are using python string formatting and not parameters to the query itself. That is a security problem in itself (SQL-Injections), but also is the problem of your syntax error. When you use numbers, your expression evaluates to
INSERT INTO table_name VALUES (100, 200)
Which is valid SQL. But with strings you get
INSERT INTO table_name VALUES (Some Text, some more text)
which is not valid (since you have no quotes ' around the strings.
To get rid of your syntax problem and of the sql-injection-problem, don't add the values to the string, pass them as a list to execute():
cursor.execute("INSERT INTO table_name VALUES (%s,%s)", (key, data[0][key]))
If you must have a dynamic table name, put that in your query string first (e.g. with % formatting), and give the actual values for your query as parameters as above (since I cannot imagine that execute will accept the table name as a parameter).
To put it in some simple sample code. Right now you are trying to do it like this:
# don't do this, this won't even work!
table_name = 'some_table'
user_name = 'Peter Smith'
user_age = 47
query = "INSERT INTO %s VALUES (%s, %s)" % (table_name, user_name, user_age)
cursor.execute(query)
That creates query
INSERT INTO some_table VALUES (Peter Smith, 100)
Which cannot work, because of the unquoted string. So you needed to do:
# DON'T DO THIS, it's bad!
query = "INSERT INTO %s VALUES ('%s', %s)" % (table_name, user_name, user_age)
That's not a good idea, because you need to know where to put quotes and where not (which you will mess up at some point). Even worse, imagine a user named named Connor O'Neal. You would get a syntax error:
INSERT INTO some_table VALUES ('Connor O'Neal', 100)
(This is also the way sql-injections are used to crush your system / steal your data). So you would also need to take care of escaping the values that are strings. Getting more complicated.
Leave those problems to python and mysql, by passing the date (not the table name) as arguments to execute!
table_name = 'some_table'
user_name = 'Peter Smith'
user_age = 47
query = "INSERT INTO " + table_name + " VALUES (%s, %s)"
cursor.execute(query, (user_name, user_age))
This way you can even pass datetime objects directly. There are other ways to put the data than using %s, take a look at this examples http://dev.mysql.com/doc/connector-python/en/connector-python-api-mysqlcursor-execute.html (that is python3 used there, I don't know which you use - but except of the print statements it should work with python2 as well, I think).