Anyone has any problems with "IF" function in Big Query?

Question

I've been writing a query in big query cause I'm still learning, so I use the sandbox to write my sentences, but I don't get success, I try so many times in so many ways but I don't. Is there some special condition to the 'IF' function that works?

SELECT stn,date,

FROM `bigquery-public-data.noaa_gsod.gsod2020`

IF(temp=9999,9, NULL, temp) AS temperature,

I tring to solve it a one week later, and already try do mane times in so many ways to arrive in one result that not return erro in the Big Query, I hope that someone analysing and gimme one answer to it! Thank you!

Answer 1

The IF function should be used in the SELECT part, example:

WITH Numbers AS (
  SELECT 10 as A, 20 as B UNION ALL
  SELECT 50, 30 UNION ALL
  SELECT 60, 60
)
SELECT
  A,
  B,
  IF(A < B, 'true', 'false') AS result
FROM Numbers

+------------------+
| A  | B  | result |
+------------------+
| 10 | 20 | true   |
| 50 | 30 | false  |
| 60 | 60 | false  |
+------------------+

In your code snippet the IF is placed the FROM without WHERE condition, it can't work like that.