Standardize Formats — Solution & ExplanationProblems / Standardize Formats / EditorialApproachThe core technique is a two-step normalization:

Normalize for comparison: UPPER(TRIM(state)) converts all variants to uppercase without surrounding whitespace.

Map to standard codes: A CASE expression with IN lists maps each group of variants to the correct abbreviation.

SQL```sqlCASEWHEN UPPER(TRIM(state)) IN ('CA', 'CALIFORNIA', 'CALIF') THEN 'CA'WHEN UPPER(TRIM(state)) IN ('NY', 'NEW YORK') THEN 'NY'...END```The ELSE UPPER(TRIM(state)) fallback handles any values not in the known mappings.Hints

First normalize the state value with UPPER() and TRIM() so you can compare uniformly.

Use CASE WHEN ... IN (...) to map multiple variants to a single standard code.

In PySpark, chain F.when().when()...otherwise() for multi-branch conditional logic.

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