Package dev.frostlake.functions.scalar.semistructured

Class MapPick

java.lang.Object
dev.frostlake.functions.BuiltInFunction
dev.frostlake.functions.scalar.semistructured.MapPick
public class MapPick extends BuiltInFunction
MAP_PICK(map, key [, key …]) and MAP_PICK(map, keyArray) — the map narrowed to the named keys. Both spellings are real overloads live (SHOW BUILTIN FUNCTIONS lists three signatures), and they do not mix: MAP_PICK(m, ARRAY_CONSTRUCT('a'), 'b') is a compile error live.

Live-verified: a key the map does not hold is silently skipped rather than added as a null (MAP_PICK(<{'a':1,'b':2}>, 'zzz') is {}), a repeated key is harmless, a NULL key picks nothing — so MAP_PICK(m, NULL) and MAP_PICK(m, NULL::ARRAY) are both the EMPTY map, not NULL — and only a NULL MAP answers NULL.

  • Constructor Details

    • MapPick

      public MapPick()

  • Method Details

    • evaluate

      public Object evaluate(List<Object> args)
      Description copied from class: BuiltInFunction
      Computes the function's result over its already-evaluated argument values. A SQL NULL argument arrives as Java null, and returning null makes the SQL result NULL.
      Specified by:
      evaluate in class BuiltInFunction
      Parameters:
      args - the argument values, in call order
      Returns:
      the function's value for these arguments, or null for SQL NULL

    • getMinArgCount

      public int getMinArgCount()
      Description copied from class: BuiltInFunction
      The fewest arguments a call to this function may pass; fewer is an argument-count error.
      Specified by:
      getMinArgCount in class BuiltInFunction
      Returns:
      the minimum accepted argument count

    • getMaxArgCount

      public int getMaxArgCount()
      Description copied from class: BuiltInFunction
      The most arguments a call to this function may pass; Integer.MAX_VALUE marks a variadic function (see BuiltInFunction.isVariadic()).
      Specified by:
      getMaxArgCount in class BuiltInFunction
      Returns:
      the maximum accepted argument count