Expression syntax

Compute column and Filter rows can use Expression mode for conditions that Simple mode cannot say in one comparison.

This is a small expression language that GeoJibe compiles into the same processing engine used by other Transform operations. It is not PostgreSQL, SQLite, or a SQL editor. You cannot write SELECT, FROM, or more than one statement.

What you can write

• Field names, including quoted names such as "parcel id"
• Numbers and quoted text ('active')
• Arithmetic: + - * / and parentheses
• Comparisons: = != <> < > <= >=
• AND, OR, NOT
• IN ('a', 'b') and NOT IN (...)
• IS NULL and IS NOT NULL
• Functions: abs, round, length, lower, upper, trim, coalesce, substr, nullif
• CAST(field AS integer|float|string)

Examples

Compute a density field:

population / area_km2

Keep busy, active rows:

population > 10000 AND status = 'active'

What is rejected

• Semicolons and SQL comments
• SELECT, FROM, UNION, and other statements
• Unknown field names
• Functions that are not in the list above

Use Validate in the editor to catch obvious mistakes before you add the operation. Running the job still uses the same rules.

See also

• Compute column
• Filter rows
• Transform operations