How to print count table query of bigquery in python?

Question

I am trying to print count of rows available in table of bigquery in python,I have written below code:

from google.cloud import bigquery def main():
    myquery = "select count(*) from `myproject.mydataset.mytable`"
    client = bigquery.Client()
    job = client.query(myquery)
    result = job.result()
    print("Total rows available: ",result)

When I execute above code it gives me output as

"Total rows available: google.cloud.bigquery.table.RowIterator object at 0x00000247B65F29E8>".

It means I am getting object value as my output. But I want to print actual count of rows available in my table(query result).

It'd probably be better if you used the Table object to do so. See the example for connecting with your table then just print table.num_rows; this operation would be free of charge and much faster. — Willian Fuks
– Willian Fuks, Commented Oct 11, 2019 at 0:06

Nico Griffioen · Accepted Answer · 2019-10-10 11:38:45Z

6

RowIterator has an attribute called total_rows.

Simply change your last statement to

 print("Total rows available: ", result.total_rows)

answered Oct 10, 2019 at 11:38

Nico Griffioen

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4 Comments

Kaustubh Ghole Over a year ago

I just tried this way but it gives me "Total rows available: None" as output. But in actual I have 634700 rows in that respective BQ table (output if i run same query from BQ console).

Stav Hacohen Over a year ago

In any case, expected result with this change only should be 1. As count returns one row.

Mark B Over a year ago

No. result.total_rows and result.num_results only report how many results have been iterated and show None or 0 before you start to iterate over the RowIterator

Ryan Loggerythm Over a year ago

results.total_rows is perfect. cloud.google.com/bigquery/docs/samples/…

Bobbylank · Accepted Answer · 2019-10-11 07:54:28Z

5

Try changing your query to

myquery = "select count(*) size from `myproject.mydataset.mytable`"
client = bigquery.Client()
job = client.query(myquery)
result = job.result()
for row in results:
    print("Total rows available: ",row.size)

edited Oct 11, 2019 at 7:54

answered Oct 10, 2019 at 14:50

Bobbylank

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Comments

Jeff Oberlander · Accepted Answer · 2023-12-15 17:44:42Z

0

BigQuery first returns a query object and from there you can get the result using .result(). But that is an Iterator object so you have to iterate to get the values. In a count (*) you know that there is only one row to iterate on so you can use "next". And that returns a row with one value in it and thus the [0].

    myquery = "select count(*) from `myproject.mydataset.mytable`"
    iterator = client.query(myquery).result()
    first_row = next(iterator)
    print("Total rows available: ",first_row[0])

edited Dec 15, 2023 at 17:44

answered Dec 14, 2023 at 19:19

Jeff Oberlander

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1 Comment

Jeremy Caney Over a year ago

Thank you for contributing to the Stack Overflow community. This may be a correct answer, but it’d be really useful to provide additional explanation of your code so developers can understand your reasoning. This is especially useful for new developers who aren’t as familiar with the syntax or struggling to understand the concepts. Would you kindly edit your answer to include additional details for the benefit of the community?

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