The following are descriptions of each comparison operator.
-
EQ
: Equal. EQ
is supported for all data types,
including lists and maps.
AttributeValueList
can contain only one
AttributeValue
element of type String, Number, Binary,
String Set, Number Set, or Binary Set. If an item contains an
AttributeValue
element of a different type than the one
provided in the request, the value does not match. For example,
{"S":"6"}
does not equal {"N":"6"}
. Also,
{"N":"6"}
does not equal {"NS":["6", "2", "1"]}
.
-
NE
: Not equal. NE
is supported for all data
types, including lists and maps.
AttributeValueList
can contain only one
AttributeValue
of type String, Number, Binary, String Set,
Number Set, or Binary Set. If an item contains an
AttributeValue
of a different type than the one provided in
the request, the value does not match. For example,
{"S":"6"}
does not equal {"N":"6"}
. Also,
{"N":"6"}
does not equal {"NS":["6", "2", "1"]}
.
-
LE
: Less than or equal.
AttributeValueList
can contain only one
AttributeValue
element of type String, Number, or Binary
(not a set type). If an item contains an AttributeValue
element of a different type than the one provided in the request, the
value does not match. For example, {"S":"6"}
does not equal
{"N":"6"}
. Also, {"N":"6"}
does not compare to
{"NS":["6", "2", "1"]}
.
-
LT
: Less than.
AttributeValueList
can contain only one
AttributeValue
of type String, Number, or Binary (not a set
type). If an item contains an AttributeValue
element of a
different type than the one provided in the request, the value does not
match. For example, {"S":"6"}
does not equal
{"N":"6"}
. Also, {"N":"6"}
does not compare to
{"NS":["6", "2", "1"]}
.
-
GE
: Greater than or equal.
AttributeValueList
can contain only one
AttributeValue
element of type String, Number, or Binary
(not a set type). If an item contains an AttributeValue
element of a different type than the one provided in the request, the
value does not match. For example, {"S":"6"}
does not equal
{"N":"6"}
. Also, {"N":"6"}
does not compare to
{"NS":["6", "2", "1"]}
.
-
GT
: Greater than.
AttributeValueList
can contain only one
AttributeValue
element of type String, Number, or Binary
(not a set type). If an item contains an AttributeValue
element of a different type than the one provided in the request, the
value does not match. For example, {"S":"6"}
does not equal
{"N":"6"}
. Also, {"N":"6"}
does not compare to
{"NS":["6", "2", "1"]}
.
-
NOT_NULL
: The attribute exists. NOT_NULL
is
supported for all data types, including lists and maps.
This operator tests for the existence of an attribute, not its data type.
If the data type of attribute "a
" is null, and you evaluate
it using NOT_NULL
, the result is a Boolean true
. This result is because the attribute "a
" exists; its data
type is not relevant to the NOT_NULL
comparison operator.
-
NULL
: The attribute does not exist. NULL
is
supported for all data types, including lists and maps.
This operator tests for the nonexistence of an attribute, not its data
type. If the data type of attribute "a
" is null, and you
evaluate it using NULL
, the result is a Boolean
false
. This is because the attribute "a
"
exists; its data type is not relevant to the NULL
comparison
operator.
-
CONTAINS
: Checks for a subsequence, or value in a set.
AttributeValueList
can contain only one
AttributeValue
element of type String, Number, or Binary
(not a set type). If the target attribute of the comparison is of type
String, then the operator checks for a substring match. If the target
attribute of the comparison is of type Binary, then the operator looks
for a subsequence of the target that matches the input. If the target
attribute of the comparison is a set ("SS
", "NS
", or "BS
"), then the operator evaluates to true if it finds
an exact match with any member of the set.
CONTAINS is supported for lists: When evaluating "
a CONTAINS b
", "a
" can be a list; however, "
b
" cannot be a set, a map, or a list.
-
NOT_CONTAINS
: Checks for absence of a subsequence, or
absence of a value in a set.
AttributeValueList
can contain only one
AttributeValue
element of type String, Number, or Binary
(not a set type). If the target attribute of the comparison is a String,
then the operator checks for the absence of a substring match. If the
target attribute of the comparison is Binary, then the operator checks
for the absence of a subsequence of the target that matches the input. If
the target attribute of the comparison is a set ("SS
", "
NS
", or "BS
"), then the operator evaluates to
true if it does not find an exact match with any member of the
set.
NOT_CONTAINS is supported for lists: When evaluating "
a NOT CONTAINS b
", "a
" can be a list; however, "b
" cannot be a set, a map, or a
list.
-
BEGINS_WITH
: Checks for a prefix.
AttributeValueList
can contain only one
AttributeValue
of type String or Binary (not a Number or a
set type). The target attribute of the comparison must be of type String
or Binary (not a Number or a set type).
-
IN
: Checks for matching elements in a list.
AttributeValueList
can contain one or more
AttributeValue
elements of type String, Number, or Binary.
These attributes are compared against an existing attribute of an item.
If any elements of the input are equal to the item attribute, the
expression evaluates to true.
-
BETWEEN
: Greater than or equal to the first value, and less
than or equal to the second value.
AttributeValueList
must contain two
AttributeValue
elements of the same type, either String,
Number, or Binary (not a set type). A target attribute matches if the
target value is greater than, or equal to, the first element and less
than, or equal to, the second element. If an item contains an
AttributeValue
element of a different type than the one
provided in the request, the value does not match. For example,
{"S":"6"}
does not compare to {"N":"6"}
. Also,
{"N":"6"}
does not compare to
{"NS":["6", "2", "1"]}