Multiplicate layer by attribute

Create multiple layers from all unique values from a selected field or expression.

Sponsored by Parcs i Jardins de Barcelona, Institut Municipal of Barcelona City Council.

Expressions

Expressions have to be written in Standard SQL, meaning they will work in the Query Builder (SQLite/GeoPackage) and the QGIS Expression Engine without modification.

1. String Manipulation

• First characters: substr("FIELD", 1, 3)
• Middle characters: substr("FIELD", 4, 2)
• Uppercase: upper("FIELD")
• Lowercase: lower("FIELD")
• Concatenate: `"FIELD1"
• Replace text: replace("FIELD", 'old', 'new')

2. Pattern Matching & Filtering

• Starts with: "FIELD" LIKE '9%'
• Ends with: "FIELD" LIKE '%9'
• Contains: "FIELD" LIKE '%9%'
• One of many: "FIELD" IN ('A', 'B', 'C')
• Case-sensitive: "FIELD" ILIKE '%a%'

3. Numbers & Logic

• Rounding: round("FIELD", 2)
• Absolute Value: abs("FIELD")
• Convert to Integer: cast("FIELD" as integer)
• Convert to Real: cast("FIELD" as real)
• If/Then Logic: CASE WHEN "A" = 1 THEN 'Yes' ELSE 'No' END
• Handle NULLs: coalesce("FIELD", 0) (Returns 0 if field is NULL)