Case Sensitivity in Power BI

1. Case Sensitivity in Power BI:
   • By default, Power BI is case-insensitive. This means that lowercase letters are treated as identical to uppercase letters.
   • For example, “Bonk” is considered the same as “BONK” in Power BI.
2. Language-Specific Behavior:
   • Different programming languages have varying rules regarding case sensitivity.
   • DAX (Data Analysis Expressions), the formula language used in Power BI, is case-insensitive.
   • However, the M language (used in Power Query) is case-sensitive, even though it coexists with DAX in the same environment.
3. Collation Style:
   • If you use Power BI Desktop, Power BI Service, or Azure Analysis Services, string comparison remains case-insensitive.
   • However, if you use SQL Server Analysis Services, you can choose between case-sensitive or case-insensitive collation styles.
4. Why Case Insensitivity:
   • When creating reports, you generally don’t want to distinguish between lowercase and uppercase.
   • In databases, strings may be stored in uppercase to avoid distinctions.
   • Power BI retains the original casing of strings but ignores it during comparisons.
   • For instance, “A” equals “a” and “JOHN” equals “John” even though they’re stored differently.
5. Unexpected Results:
   • When your tables store a mix of lowercase and uppercase strings, be aware of potential unexpected outcomes.
   • Knowing this in advance helps you design your models effectively.

Remember, while case sensitivity can be a complex matter, Power BI’s default choice of case-insensitivity aligns well with reporting needs!