Bigquery select distinct values

Question

How to select distinct values in Google Bigquery?

Query:

SELECT DISTINCT cc_info
FROM user
WHERE date = ?

Thanks!

Answer 1

SELECT cc_info
FROM user
WHERE date = ?
GROUP BY cc_info

Answer 2

For all who have come to find the DISTINCT method in BigQuery, and who needs to use unique field feature for tables having large columns, using GROUP BY as mentioned by tning won't be possible.

As of 2020, BigQuery has DISTINCT modifier. You need to wrap your query as:

SELECT DISTINCT usr.cc_info
FROM (
  SELECT *
  FROM user
  WHERE date = ?
) usr

This could be very handy for people shifting from other SQL products.

Answer 3

Try using group by

SELECT cc_info
FROM user
WHERE date = ?
group by cc_info

Answer 4

SELECT COUNT(DISTINCT cc_info)
FROM user
WHERE date = ?

is NOT the right query, because DISTINCT is a statistical approximation and is not guaranteed to be exact. See https://cloud.google.com/bigquery/docs/reference/legacy-sql#countdistinct

So better approach is

select EXACT_COUNT_DISTINCT(cc_info) from user where date = ?

Answer 5

Simply use group by,

SELECT cc_info
FROM user
WHERE date = ?
GROUP BY cc_info

If you want to COUNT over DISTINCT values you can use,

SELECT COUNT(DISTINCT cc_info)
FROM user
WHERE date = ?

Answer 6

This is another way to achieve your goal (in case anyone else needs it) which works in the current BigQuery 2020.

SELECT colname FROM table1
UNION DISTINCT 
SELECT colname FROM table2
UNION DISTINCT
.
.
.
SELECT colname FROM tableN 

My reference was this article.