How To Fix DDLS320 - String column & is not possible with SELECT DISTINCT

SAP Error Message - Details

• Message type: E = Error

• Message class: DDLS - For DDL source handling

• Message number: 320

• Message text: String column & is not possible with SELECT DISTINCT

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message DDLS320 - String column & is not possible with SELECT DISTINCT ?

  The SAP error message DDLS320 indicates that there is an issue with using the SELECT DISTINCT statement on a string column in a database table. This error typically arises when the database system does not support the use of SELECT DISTINCT on certain data types, particularly string columns, due to the way it handles distinct values.
  Cause:
  The primary cause of this error is that the database engine (such as SAP HANA, Oracle, or others) has limitations or specific requirements regarding the use of SELECT DISTINCT with string columns. This can happen if:
  
  The string column has a large size or is of a type that does not support distinct operations efficiently.
  The database is configured in a way that restricts the use of SELECT DISTINCT on certain data types.
  There are underlying issues with the data model or the way the query is structured.
  
  Solution:
  To resolve the DDLS320 error, you can consider the following approaches:
  
  
  Modify the Query:
  
  Instead of using SELECT DISTINCT, you can try to use a different approach to achieve the same result. For example, you can use GROUP BY on the string column to get unique values:
  SELECT column_name
  FROM table_name
  GROUP BY column_name;
  
  
  
  
  Check Data Types:
  
  Ensure that the data types of the columns you are querying are appropriate for the operations you are performing. If possible, consider changing the data type of the column to a more suitable type that supports distinct operations.
  
  
  
  Limit the Size of the String:
  
  If the string column is very large, consider truncating the string to a manageable size for the distinct operation. This can be done using string functions in SQL.
  
  
  
  Database Configuration:
  
  Check the database configuration and settings. There may be specific settings that can be adjusted to allow for SELECT DISTINCT on string columns.
  
  
  
  Consult Documentation:
  
  Refer to the documentation of the specific database you are using to understand its limitations and best practices regarding SELECT DISTINCT and string columns.
  
  
  
  Use a Subquery:
  
  If the above solutions do not work, consider using a subquery to first filter the data and then apply the distinct operation:
  SELECT DISTINCT column_name
  FROM (SELECT column_name FROM table_name) AS subquery;
  
  
  
  
  Related Information:
  
  Database Documentation: Always refer to the specific database documentation for details on supported SQL operations and limitations.
  SAP Notes: Check SAP Notes for any known issues or patches related to this error message.
  Performance Considerations: Be aware that using SELECT DISTINCT can have performance implications, especially on large datasets. Always test queries for performance.
  
  By following these steps, you should be able to resolve the DDLS320 error and successfully execute your query.