Explain ETL vs ELT

Answer

ETL

Data is:

Extract → Transform → Load

Transformation happens in Talend server before loading into DB.

ELT

Extract → Load → Transform

Data first loaded into target warehouse (Snowflake/BigQuery), then transformed using SQL.

Real-Time

• Traditional DWH → ETL
• Cloud DWH → ELT

Interview Point

“ELT is preferred for cloud warehouses because they provide massive parallel processing.”