Error ORA-00920: “Invalid relational operator” in Apache Superset when using embedding

Apache Superset is an amazing tool for data visualization and exploration. However, like any other powerful tool, it’s not immune to errors. One of the most frustrating errors you might encounter is the “Invalid relational operator” error, specifically when using embedding in Superset. In this article, we’ll dive into the world of ORA-00920 errors and show you how to fix them once and for all!

About the Error

The ORA-00920 error is thrown when the Oracle database (which Superset uses under the hood) encounters an invalid relational operator in your query. In simpler terms, it means that the database is complaining about the way you’re trying to compare or filter your data.

This error often appears when using embedding in Superset, which allows you to create complex data visualizations by combining multiple filters and aggregation functions. However, if you’re not careful, you might end up with an invalid query that trips up the database.

Common Causes of the Error

Before we dive into the solutions, let’s explore some common scenarios that might lead to the ORA-00920 error:

• Mismatched data types: When you’re comparing two columns with different data types, the database might get confused. For example, trying to compare a string column with a date column.
• Invalid operator syntax: Using the wrong operator or syntax can lead to this error. For instance, using `=` instead of `==` or forgetting to enclose a string value in single quotes.
• Nested filter issues: When using embedding, it’s easy to create nested filters that can cause the database to throw an error. This might happen when you’re using multiple `AND` or `OR` operators.
• Aggregate function mishaps: Using aggregate functions like `SUM` or `MAX` with the wrong syntax or data types can also trigger this error.

Solution 1: Check Your Data Types

One of the most common causes of the ORA-00920 error is mismatched data types. To avoid this, make sure you’re comparing columns with compatible data types.

Here’s an example of a faulty query that might cause this error:

SELECT *
FROM my_table
WHERE my_string_column = 123;

In this example, `my_string_column` is a string column, but we’re trying to compare it to an integer value `123`. To fix this, we need to enclose the value in single quotes:

SELECT *
FROM my_table
WHERE my_string_column = '123';

Solution 2: Validate Your Operator Syntax

Another common mistake is using the wrong operator syntax. Here are some examples of invalid syntax that might lead to the ORA-00920 error:

Invalid Syntax	Valid Syntax
WHERE my_column = 123abc	WHERE my_column = '123abc'
WHERE my_column == 123	WHERE my_column = 123
WHERE my_column LIKE 123%	WHERE my_column LIKE '123%'

Make sure to double-check your operator syntax and data types to avoid these common mistakes.

Solution 3: Simplify Your Filters

When using embedding in Superset, it’s easy to create complex filters that can lead to the ORA-00920 error. To avoid this, try simplifying your filters by breaking them down into smaller, more manageable parts.

Here’s an example of a complex filter that might cause an error:

SELECT *
FROM my_table
WHERE (
  (my_column = 'value1' AND my_column2 > 10)
  OR (my_column = 'value2' AND my_column2 < 5)
) AND my_column3 = 'value3';

Instead, try breaking it down into smaller filters:

SELECT *
FROM (
  SELECT *
  FROM my_table
  WHERE my_column = 'value1' AND my_column2 > 10
) AS subquery
WHERE my_column3 = 'value3';

SELECT *
FROM (
  SELECT *
  FROM my_table
  WHERE my_column = 'value2' AND my_column2 < 5
) AS subquery
WHERE my_column3 = 'value3';

By breaking down your filters, you can avoid the ORA-00920 error and make your queries more readable and maintainable.

Solution 4: Check Your Aggregate Functions

When using aggregate functions like `SUM` or `MAX`, make sure you're using the correct syntax and data types.

Here's an example of an invalid query that might cause an error:

SELECT SUM(my_string_column)
FROM my_table;

In this example, we're trying to use the `SUM` function on a string column, which is invalid. To fix this, we need to use a different aggregate function, such as `COUNT` or `GROUP_CONCAT`:

SELECT COUNT(my_string_column)
FROM my_table;

SELECT GROUP_CONCAT(my_string_column)
FROM my_table;

Make sure to choose the correct aggregate function and data type to avoid the ORA-00920 error.

Conclusion

The ORA-00920 error can be frustrating, but it's usually caused by simple mistakes in your query syntax or data types. By following the solutions outlined in this article, you can fix the error and get back to visualizing your data with Apache Superset.

Remember to check your data types, validate your operator syntax, simplify your filters, and check your aggregate functions. With a little patience and attention to detail, you'll be able to overcome the ORA-00920 error and unlock the full potential of Superset.

Additional Tips

1. Use Superset's built-in query editor to test and validate your queries before running them.
2. Use the Oracle documentation to reference the correct syntax and data types for your queries.
3. Test your queries with small datasets before applying them to large datasets.
4. Use descriptive column names and aliases to make your queries more readable and maintainable.

By following these tips and solutions, you'll be well on your way to becoming a Superset master and avoiding the ORA-00920 error for good!

Frequently Asked Question

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