>>I don't think your searches was for exact matches. Otherwise you would know that by now. MS SQL server datetime is only have a sensitivity of 3 milliseconds.

More typically BETWEEN or >=?MyDateTime used in parameterized queries without issue since last century. These are converted to SQL @parameterized queries via ODBC for execution plan caching and SQL-injection-proof development. The identical parameterized query also works equally well for Oracle vs SQL Server despite different datetime layouts if you concatenate your parameters into SQL

>>I don't understand what your comment "which casting to string often did not" means at all.

Per Rick's examples, explicit or implicit casting won't always benefit from an index on a datetime field. I don't believe SQL Server stores datetime as a string, so comparing datetime to a string value using LIKE or anything else, risks a table scan. JMHO, I'm a great believer in KISS and parameterized queries are as simple as it gets IMHO.