ORA-01427

ORA-01427: single-row subquery returns more than one row

Cause:
You tried to execute an SQL statement that contained a subquery that returns more than one row.

Action:
The options to resolve this Oracle error are:
Rewrite your query so that the subquery only returns one row.
Change your query to use one of the following functions against your subquery results:
ANY, ALL, IN, NOT IN

sde log:
db_array_fetch_attrs OCI Fetch Error (1427)
load_buffer error -51

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All ESRI ArcSDE errors in the blog can found at: ArcSDE Errors