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Description

Currently, in the SQL conversion of SeaTunnel, the COALESCE(args0, args1, args2, ...) function does not support casting args1 or args2 to the type of args0.

For example, args0 is of string type, args1 is of int type, and args2 is of double type, which will cause the wrong data type to be passed to the downstream. We should cast the data to the type indicated by args0(string).

Current Behavior

When trying to use COALESCE function directly on a string field:

SELECT COALESCE(str_field, 1) FROM my_table

Will output data type 1 <-> int

Expected Behavior

The COALESCE function should automatically handle type conversion, converting any other type to args0 type output

Changes

• docs
  • https://github.com/apache/seatunnel/blob/dev/docs/en/transform-v2/sql-functions.md#coalesce
  • https://github.com/apache/seatunnel/blob/dev/docs/zh/transform-v2/sql-functions.md#coalesce
• testcase
  • https://github.com/apache/seatunnel/tree/dev/seatunnel-e2e/seatunnel-transforms-v2-e2e/seatunnel-transforms-v2-e2e-part-2/src/test/resources/sql_transform
  • test all types cast

Usage Scenario

No response

Related issues

No response

Are you willing to submit a PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct