PostgresOperator allows us to use a SQL file as the query. However, when we do that, the standard way of passing template parameters no longer works.

For example, if I have the following SQL query:

 SELECT column_a, column_b FROM table_name WHERE column_a = {{ some_value }} 

Airflow will not automatically pass the some_value variable as the parameter.

In this situation, I have to use the parameters attribute of the PostgresOperator:

    params={"some_value":"'the value I want'"},

Note that, I had to wrap the value into single quotes! Because in Postgres double quotes are used to reference a columns, tables, or functions. String literals, on the other hand, are inside single quotes.

In the query.sql file, I have to change the template variable to params.some.value:

 SELECT column_a, column_b FROM table_name WHERE column_a = {{ params.some_value }} 
Older post

Use regexp_replace to replace a matched string with a value of another column in PySpark

Use regex to replace the matched string with the content of another column in PySpark

Newer post

Speed up counting the distinct elements in a Spark DataFrame

Use HyperLogLog to calculate the approximate number of distinct elements in Apache Spark