Adding SQL Queries in For Loop in Python

Question

Is there a way to add SQL queries in a For Loop in python where the table names and database names are variable? Something like this:

database = []
tables= []
column = []

for x in database: 
    for y in tables:
        for z in column:
            SQL = "select * from x.y where z is NOT NULL;"
            cursor.execute(sql)`enter code here`

Answer 1

Just use string formatting. In your example:

database = []
tables= []
column = []

for x in database: 
    for y in tables:
        for z in column:
            SQL = "select * from {x}.{y} where {z} is NOT NULL;".format(x=x, y=y, z=z)
            cursor.execute(sql)

It's a single example of python string formatting, but you either can use string concatenation, % formatting or f-strings.

Answer 2

Just use .format() method of string object to get the sql query string:

SQL = "select * from {}.{} where {} is NOT NULL;".format(x, y, z)

Or append values like this:

SQL = "select * from " + str(x) + "." + str(y) + " where " + str(z) + " is NOT NULL;"

I recommend the first solution.