Implicit Conversion in AzureSQLDB

Question

Hi Team,

Could you please what is this warning?

Answer 1

The warning is informational. If your query performed slowly, or you noticed that cardinality estimates were incorrect, the warning would give you information about where to look for a possible cause.

This means also implicit type conversions cannot effectively use an index. The query optimizer uses the index cardinality to generate an optimal query plan for a given query. It also uses the index cardinality to decide whether to use the index or not in the join operations and WHERE clause. For performance, the ideal is to have the data types match, instead of allowing the implicit conversion to happen.