SET configuration in SQL DLT pipeline not working

[oteng]

I'm not able to get the SET command to work when using sql in DLT pipeline.

I am copying the code from this documentation https://docs.databricks.com/workflows/delta-live-tables/delta-live-tables-sql-ref.html#sql-spec (relevant code below). When I run something similar, I get empty value for ${startDate}. Any way to set a variable for the sql inside a notebook for DLT pipelines?

This is the code in the documentation

SET startDate='2020-01-01';
 
CREATE OR REFRESH LIVE TABLE filtered
AS SELECT * FROM src
WHERE date > ${startDate}

This is the code I tried running:

SET startDate='2020-01-01';
 
CREATE OR REFRESH LIVE TABLE filtered
AS SELECT * FROM (select '2021-01-01' as date)
WHERE date > ${startDate}

This is my error message when running dlt pipeline. It is setting ${startDate} to empty string. It works when I set the configuration value inside the settings of the dlt pipeline but not when I specify it in the notebook.:

[Kaniz]

Hi @Oliver Teng​, Since the date column is not part of any table in the query, the condition WHERE date > ${startDate}will result in an error.

To fix this, you can either remove the subquery and directly specify the value of '2021-01-01'

in the WHERE clause:

SET startDate='2020-01-01';
 
CREATE OR REFRESH LIVE TABLE filtered
AS SELECT * FROM (SELECT '2021-01-01' as date)
WHERE '2021-01-01' > ${startDate};

Or you can modify the subquery to include the date column in a table:

SET startDate='2020-01-01';
 
CREATE OR REFRESH LIVE TABLE filtered
AS SELECT * FROM (
  SELECT ’2021-01-01’ as date
  FROM (SELECT 1) -- Add a ***** table to create a single-row subquery
) t
WHERE date > ${startDate};

In this example, we add a ***** table with a single row to the subquery to create a table alias t with a single column date. We can then reference the date in the WHERE clause.

[Anonymous]

Hi @Oliver Teng​ 

Hope all is well! Just wanted to check in if you were able to resolve your issue and would you be happy to share the solution or mark an answer as best? Else please let us know if you need more help. 

We'd love to hear from you.

Thanks!