Update table using with temp CTE

Question

%sql
with temp1 as 
(
  select req_id from table1 order by timestamp desc limit 8000000
)
    
update table1  set label = '1'  where req_id in temp1 and req_query like '%\<\/script\>%' 

update table1  set label = '1'  where req_id in temp1 and req_query like '%aaaaa%' 
update table1  set label = '1'  where req_id in temp1 and req_query like '%bbbb%' 

getting error:

com.databricks.backend.common.rpc.DatabricksExceptions$SQLExecutionException: org.apache.spark.sql.catalyst.parser.ParseException: mismatched input 'in' expecting {, ';'}(line 6, pos 93)

can someone advise? what will be less costly to ask the database the same question?

select req_id from table1 order by timestamp desc limit 8000000

Answer 1

This is not allowed: where req_id in temp1 . temp1 is not a list, but the result of a query and should be used like another table.
You might rather write something like this:

update table1
   set label = '1'
 where req_id in (select req_id from table1 order by timestamp desc limit 8000000)
   and req_query like '%\<\/script\>%' 

Answer 2

You can use update with join instead of IN clause. Delta does not support updating tables using inner join but you can use MERGE I think. Something like this:

WITH temp1 AS (
  SELECT req_id FROM table1 ORDER BY timestamp DESC LIMIT 8000000
)

MERGE INTO table1 a 
USING temp1 b
ON (a.req_id = b.req_id)
WHEN MATCHED THEN
UPDATE SET a.label = CASE WHEN a.req_query LIKE '%\<\/script\>%' THEN '1'
                          WHEN a.req_query LIKE '%aaaaa%'        THEN '2'
                          WHEN a.req_query LIKE '%bbbb%'         THEN '3'
                          ELSE a.label 
                     END