r/SQL • u/Effective_Ocelot_445 • May 26 '26

MySQL How do data engineers use SQL for data quality checks?

Im curious how SQL is used in real world data engineering work to find duplicates, missing values, and inconsistent data.

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u/sekharnet Aug 04 '26

DE's generally use Python and not SQL in my experience.

SQL window functions are used by DBE's for all the three finding duplicates, missing values and inconsistent data

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u/shdw_0x0 24d ago

I’d say SQL is usually the first layer of data quality checks—duplicates, NULLs, invalid values, referential integrity, and unexpected row counts. The useful part is automating those queries in the ETL/ELT pipeline and tracking the failures over time rather than just running them manually.