Expression evaluation error at function a!queryEntity [line 21]: An error occurred while retrieving the data.

Hi All,

Writing my approach and solution I got, so that it might be helpful to others if they faced the same issue.

Thank you for all your responses when i got this issue i check for the below things.

1)Checked for the columns types of data type and view for any miss-match (everything is fine).
2)Checked for date fields data , it don't have any invalid data(i.e 0000-00-00 or past date(like 200 years ago which appian won't support))
3)Don't have huge data in the view(so no time out issue) .
4)No duplicate data for the primary key in the view.

everything was fine then checked for logs and found the following error.

"Caused by: java.sql.SQLException: Illegal mix of collations (utf8mb4_unicode_ci,COERCIBLE) and (utf8mb4_general_ci,COERCIBLE) for operation '=' "

This is because collation of the column is changing to utf8mb4_unicode_ci when i create a column with combination and concat of two columns(ex: row_id(10) and row_num(3) so my id will be "10-3" ).

Below Article give you the clear information for the changes required.

community.appian.com/.../kb-1770-java-sql-sqlexception-illegal-mix-of-collations-for-operation-operator_5f00_name-causes-error-while-loading-records-and-tasks

We raised Appian support ticket to do those changes.

Thanks,
Bhargavi P

Hi All,

Writing my approach and solution I got, so that it might be helpful to others if they faced the same issue.

Thank you for all your responses when i got this issue i check for the below things.

1)Checked for the columns types of data type and view for any miss-match (everything is fine).
2)Checked for date fields data , it don't have any invalid data(i.e 0000-00-00 or past date(like 200 years ago which appian won't support))
3)Don't have huge data in the view(so no time out issue) .
4)No duplicate data for the primary key in the view.

everything was fine then checked for logs and found the following error.

"Caused by: java.sql.SQLException: Illegal mix of collations (utf8mb4_unicode_ci,COERCIBLE) and (utf8mb4_general_ci,COERCIBLE) for operation '=' "

This is because collation of the column is changing to utf8mb4_unicode_ci when i create a column with combination and concat of two columns(ex: row_id(10) and row_num(3) so my id will be "10-3" ).

Below Article give you the clear information for the changes required.

community.appian.com/.../kb-1770-java-sql-sqlexception-illegal-mix-of-collations-for-operation-operator_5f00_name-causes-error-while-loading-records-and-tasks

We raised Appian support ticket to do those changes.

Thanks,
Bhargavi P