I am using below query to delete duplicates records from bigquery using standard sql. but it is throwing error
with cte as (
select * ,row_number()over (partition by CallRailCallId order by CallRailCallId) as rn
from `encoremarketingtest.EncoreMarketingTest.CallRailCall2` )
delete
from cte
where rn>1
Query Failed Error: Syntax error: Expected "(" or keyword SELECT but got keyword DELETE at [5:5]
Could anyone help me on the correct approach in BigQuery?
Option #1
CREATE OR REPLACE TABLE `project.dataset.your_table` AS
SELECT * EXCEPT(rn)
FROM (
SELECT *, ROW_NUMBER() OVER(PARTITION BY CallRailCallId ORDER BY CallRailCallId) rn
FROM `project.dataset.your_table`
)
WHERE rn = 1
Option #2
CREATE OR REPLACE TABLE `project.dataset.your_table` AS
SELECT row.*
FROM (
SELECT ARRAY_AGG(t ORDER BY CallRailCallId LIMIT 1)[OFFSET(0)] row
FROM `project.dataset.your_table` t
GROUP BY CallRailCallId
)
As you might noticed, above options using DDL(CREATE TABLE) approach and that is where it is possible to use just one known (from your question) column - CallRailCallId
Also, note - ORDER BY CallRailCallId plays no real role there because GROUP BY and PARTITION BY are by exactly same filed. But if you change the field this will control which exactly row (out of few duplicates) to "survive" (For example ORDER BY ts DESC - see below option for what ts might be)
Option #3
This option uses DML(DELETE FROM) but requires some extra column to be used to serve as a tie-breaker
For example you have ts TIMESTAMP field and you want the most recent (based on ts) row to survive
DELETE FROM `project.dataset.your_table`
WHERE STRUCT(CallRailCallId, ts) NOT IN (
SELECT AS STRUCT CallRailCallId, MAX(ts) ts
FROM `project.dataset.your_table`
GROUP BY CallRailCallId
)
