Using ISO year instead of raw year

Looker Q&A Looker
1

Is there a way to choose not year by the name (fx. “2025”), but by ISO year?
Meaning fx that ISO 2025 will include 2024-30-12 and 2024-31-12, and exclude 2025-29-12, 2025-30-12 and 2025-31-12?

Week_of_year is already done the ISO way, but when I filter by a year for comparison, it does not take the overlap into account.

2

Filter by ISO year is not available yet, and the default year takes it by the name.

To implement your capabilities you might wanna create a date to ISO-year mapping and perform a blend.

3

Hey,

Hope you’re keeping well.

Looker’s native year dimension uses the calendar year, so filtering by it won’t align with ISO week/year boundaries. To work with ISO years, you’ll need to define a custom dimension in LookML using extract_iso_year logic via SQL from your database, for example:

lookml
dimension: iso_year {
  type: number
  sql: EXTRACT(ISOYEAR FROM ${TABLE}.date_column) ;;
}
```  

Once defined, you can use `iso_year` in filters and comparisons, ensuring it matches ISO week conventions. If you’re working in Looker Studio, you can achieve similar behavior with a calculated field using your data source’s ISO year function.

Thanks and regards,  
Taz
4

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