How To Fix SDDL_PARSER_MSG030 - UNION must not contain any LOB columns in the selection list

SAP Error Message - Details

• Message type: E = Error

• Message class: SDDL_PARSER_MSG - Message Class for DDL Parser

• Message number: 030

• Message text: UNION must not contain any LOB columns in the selection list

What causes this issue?

The selection list of a UNION cannot have columns with the type STRING,
RAWSTRING, LCHR, or LRAW.
Elements with these ABAP Dictionary data types are known as LOBs (Large
Objects).

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message SDDL_PARSER_MSG030 - UNION must not contain any LOB columns in the selection list ?

  The SAP error message SDDL_PARSER_MSG030 indicates that there is an issue with a SQL query that is attempting to use a UNION operation, which includes LOB (Large Object) columns in the selection list. In SAP HANA and other SQL databases, LOB columns (such as BLOBs for binary data or CLOBs for character data) cannot be included in a UNION operation due to the way these data types are handled.
  Cause:
  The error occurs when a SQL statement attempts to combine results from multiple SELECT statements using a UNION, and at least one of those SELECT statements includes a LOB column. The SQL standard and many database systems, including SAP HANA, restrict the use of LOB columns in UNION operations because they can lead to complications in data handling and performance.
  Solution:
  To resolve this error, you need to modify your SQL query to ensure that LOB columns are not included in the selection lists of the SELECT statements that are part of the UNION. Here are some potential solutions:
  
  
  Remove LOB Columns: If the LOB columns are not necessary for the result set, simply remove them from the SELECT statements involved in the UNION.
  SELECT column1, column2 FROM table1
  UNION
  SELECT column1, column2 FROM table2;
  
  
  Use a Different Approach: If you need to include LOB columns in your results, consider using alternative methods such as:
  
  Using separate queries for each SELECT statement and then combining the results in your application logic.
  Using JOINs instead of UNION if the data can be logically combined that way.
  
  
  
  Aggregate LOB Data: If you need to summarize or aggregate LOB data, consider using functions that can handle LOBs appropriately, but keep in mind that you still cannot use them directly in a UNION.
  
  
  Related Information:
  
  Documentation: Refer to the SAP HANA SQL and System Views Reference for more details on SQL syntax and restrictions.
  Performance Considerations: Be aware that LOB columns can impact performance, so it's often best to minimize their use in operations that require high efficiency.
  Testing: After making changes to your SQL query, test it thoroughly to ensure that it returns the expected results without errors.
  
  By following these guidelines, you should be able to resolve the SDDL_PARSER_MSG030 error and successfully execute your SQL queries.