Nulls¶
coalesce¶
Description |
Examples |
|---|---|
Arguments:
FUNCTION(function-expression{0|1}),
VALUES(value-expression{1})
Returns the first value in VALUES that is not
null. If the
FUNCTION argument is specified then the first value that returns a
true value for the expression is returned. |
["coalesce", "_S.tags"]Returns the first value in the source entity’s
tags
field that is not null.["coalesce",["gt", "_.expenses", 1000], "_S.hobbies"]Returns the first hobby that has expenses greater than 1000.
|
coalesce-args¶
Description |
Examples |
|---|---|
Arguments:
VALUES(value-expression{>=1})
Returns the first argument in VALUES that is not
null. The function is
evaluating the arguments in order and will short-circuit once there is a
non-null value. If all arguments evaluate to null then the function
will return null.
|
["coalesce-args", "_S.one", "_S.two", "_S.three"]Returns the the value of
_S.two if that evaluates to non-null and
_S.one evaluates to null.["coalesce-args",null, null, 123, 236]Returns
123 as that is the first non-null argument.["coalesce-args",null, ["list"], 123, 236]Returns
[] as that is the first non-null argument. |
if-null¶
Description |
Examples |
|---|---|
Arguments:
VALUE(value-expression{1})
FALLBACK-VALUE(value-expression{1})
If
is-null is false for VALUE then VALUE is returned, otherwise
FALLBACK-VALUE is returned. |
["if-null", null, 2]Returns
2.["if-null", 1, 2]Returns
1.["if-null", ["list", null], 2]Returns
2.["if-null", ["list", null, 123], 2]Returns
2.["if-null", ["list", 1, "12345"], 2]Returns
[1, "12345"]. |
is-not-null¶
Description |
Examples |
|---|---|
Arguments:
VALUES(value-expression{1})
Boolean function that returns
false if value is either null, an
empty list, or a list where the first element in the list is null. |
["is-not-null", null]Returns
false.["is-not-null", 1]Returns
true.["is-not-null", ["list"]]Returns
false.["is-not-null", ["list", null]]Returns
false.["is-not-null", ["list", null, 123]]Returns
false. Note that the function only looks at the first value
in the list.["is-not-null", ["list", 1, "12345"]]Returns
true. |
is-null¶
Description |
Examples |
|---|---|
Arguments:
VALUES(value-expression{1})
Boolean function that returns
true if value is either null, an
empty list, or a list where the first element in the list is null. |
["is-null", null]Returns
true.["is-null", 1]Returns
false.["is-null", ["list"]]Returns
true.["is-null", ["list", null]]Returns
true.["is-null", ["list", null, 123]]Returns
true. Note that the function only looks at the first value
in the list.["is-null", ["list", 1, "12345"]]Returns
false. |