Mid-levelMid (3–6 yrs)SQLRedisMongoDBMicrosoftOracleAmazon
Clustered vs non-clustered index
Explain clustered vs non-clustered indexes and when covering indexes help.
Answers use simple, clear English.
Quick interview answer
Clustered index defines physical row order (usually PK). Non-clustered is a separate structure pointing to rows. A covering index includes all columns a query needs so the engine avoids key lookups.
Detailed answer
Clustered index defines physical row order (usually PK). Non-clustered is a separate structure pointing to rows. A covering index includes all columns a query needs so the engine avoids key lookups. Too many indexes slow writes.
midseniorfull-stack#sql#indexing