Catches an error in a DAX expression and returns a fallback value. Like ISERROR it triggers additional storage engine scans, so cleaning data upstream in Power Query, testing with IF, or calling DIVIDE are better options.
Read more: Microsoft Learn
In the Ultra Transcenders books
Each book explains IFERROR in context, with comparison tables and the common traps.
Terms in this definition
- DAX
Short for Data Analysis Expressions, the formula language you write measures, calculated columns and row-level security rules in, within tabular semantic models in Power BI, Excel Power Pivot or Analysis Services.
- LIKE
Compares strings with a pattern that can contain the % and _ wildcards. Because it only understands character patterns, searching big volumes of text this way is much slower than using full-text search.
- ISERROR
Returns TRUE if a value is an error. Because it slows measures down in the same way IFERROR does, it is better left out of them.
- Storage engine
VertiPaq: the in-memory column store behind Import and Direct Lake models. It scans data and does early aggregation, handing results up to the formula engine, which plans queries; most DAX performance work aims to lighten its load.
- DIVIDE
A DAX function for safe division: when the denominator is zero or BLANK it gives BLANK, or a fixed alternative value if you supply one. It is preferred over the / operator whenever the denominator isn't a constant.
- Table options
Set only at creation with
OPTIONS, these key-value storage settings can't be altered or dropped afterwards; on Delta tables they also show up among the table properties.