Question

I have a loop processing the output of an MySQLdb queries:

for item in getItems()
    . . . 

where getResults() is returning the output of a cursor.fetchall().

How can I modify getItems() so it combines the fetchall() returns of several different queries? That is, once the results of the first query are exhausted, I want the loop to begin working on the results of a second query.

Answer 1

If both queries have a similar column structure, you could consider using MySQL to combine the two SQL queries using the UNION keyword.

SELECT a, b, c
FROM table_x
UNION
SELECT d,e,f
FROM table_y

Otherwise, it may be easier to define getItems as a generator.

def getItems():
    cursor.execute(query1)
    for row in cursor.fetchall():
        yield row
    cursor.execute(query2)
    for row in cursor.fetchall():
        yield row

gen = getItems()

for item in gen:
    ...