Other Functions [Back to TOC]

uuid

• Syntax:

   uuid()
  

• Generates a uuid.

• Arguments:

  • none

• Return Value:

  • a generated, random uuid.

is_null

• Syntax:

   is_null(expr)
  

• Checks whether the given expression is evaluated to be a null value.

• Arguments:

  • expr : an expression (any type is allowed).

• Return Value:

  • a boolean on whether the variable is a null or not,
  • a missing if the input is missing.

• Example:

   { "v1": is_null(null), "v2": is_null(1), "v3": is_null(missing) };
  

• The expected result is:

   { "v1": true, "v2": false }
  

is_missing

• Syntax:

   is_missing(expr)
  

• Checks whether the given expression is evaluated to be a missing value.

• Arguments:

  • expr : an expression (any type is allowed).

• Return Value:

  • a boolean on whether the variable is a missing or not.

• Example:

   { "v1": is_missing(null), "v2": is_missing(1), "v3": is_missing(missing) };
  

• The expected result is:

   { "v1": false, "v2": false, "v3": true }
  

is_unknown

• Syntax:

   is_unknown(expr)
  

• Checks whether the given variable is a null value or a missing value.

• Arguments:

  • expr : an expression (any type is allowed).

• Return Value:

  • a boolean on whether the variable is a null/``missingvalue (true) or not (false`).

• Example:

   { "v1": is_unknown(null), "v2": is_unknown(1), "v3": is_unknown(missing) };
  

• The expected result is:

   { "v1": true, "v2": false, "v3": true }
  

len

• Syntax:

  len(array)

• Returns the length of the array array.

• Arguments:

  • array : an array, multiset, null, or missing, represents the collection that needs to be checked.

• Return Value:

  • an integer that represents the length of input array or the size of the input multiset,
  • missing if any argument is a missing value,
  • null if any argument is a null value but no argument is a missing value.

• Example:

   len(["Hello", "World"])
  

• The expected result is:

   2
  

not

• Syntax:

   not(expr)
  

• Inverts a boolean value

• Arguments:

  • expr : an expression

• Return Value:

  • a boolean, the inverse of expr,
  • missing if any argument is a missing value,
  • null if any argument is a null value but no argument is a missing value,
  • other non-boolean argument value will cause a type error.

• Example:

   { "v1": `not`(true), "v2": `not`(false), "v3": `not`(null), "v4": `not`(missing) };
  

• The expected result is:

   { "v1": false, "v2": true, "v3": null }
  

range

• Syntax:

   range(start_numeric_value, end_numeric_value)
  

• Generates a series of bigint values based start the start_numeric_value until the end_numeric_value.

• Arguments:

  • start_numeric_value: a tinyint/smallint/integer/bigint value representing the start value.
  • end_numeric_value: a tinyint/smallint/integer/bigint value representing the max final value.

• Return Value:

  • an array that starts with the integer value of start_numeric_value and ends with the integer value of end_numeric_value, where the value of each entry in the array is the integer successor of the value in the preceding entry.

• Example:

    range(0, 3);
  

• The expected result is:

   [ 0, 1, 2, 3 ]
  

switch_case

• Syntax:

   switch_case(
       condition,
       case1, case1_result,
       case2, case2_result,
       ...,
       default, default_result
   )
  

• Switches amongst a sequence of cases and returns the result of the first matching case. If no match is found, the result of the default case is returned.

• Arguments:

  • condition: a variable (any type is allowed).
  • caseI/default: a variable (any type is allowed).
  • caseI/default_result: a variable (any type is allowed).

• Return Value:

  • caseI_result if condition matches caseI, otherwise default_result.

• Example 1:

   switch_case(
       "a",
       "a", 0,
       "x", 1,
       "y", 2,
       "z", 3
   );
  

• The expected result is:

   0
  

• Example 2:

   switch_case(
       "a",
       "x", 1,
       "y", 2,
       "z", 3
   );
  

• The expected result is:

   3
  

deep_equal

• Syntax:

    deep_equal(expr1, expr2)
  

• Assess the equality between two expressions of any type (e.g., record, arrays, or multiset). Two objects are deeply equal iff both their types and values are equal.

• Arguments:

  • expr1 : an expression,
  • expr2 : an expression.

• Return Value:

  • true or false depending on the data equality,
  • missing if any argument is a missing value,
  • null if any argument is a null value but no argument is a missing value.

• Example:

   deep_equal(
              {
                "id":1,
                "project":"AsterixDB",
                "address":{"city":"Irvine", "state":"CA"},
                "related":["Hivestrix", "Preglix", "Apache VXQuery"]
              },
              {
                "id":1,
                "project":"AsterixDB",
                "address":{"city":"San Diego", "state":"CA"},
                "related":["Hivestrix", "Preglix", "Apache VXQuery"]
              }
   );
  

• The expected result is:

   false