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Signed-off-by: jayzhan211 <[email protected]>
apache · Nov 15, 2023 · 82cb693 · 82cb693
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diff --git a/datafusion/physical-expr/src/array_expressions.rs b/datafusion/physical-expr/src/array_expressions.rs
@@ -39,7 +39,6 @@ use datafusion_common::{
 };
 
 use itertools::Itertools;
-use std::collections::HashSet;
 
 macro_rules! downcast_arg {
     ($ARG:expr, $ARRAY_TYPE:ident) => {{

diff --git a/docs/source/user-guide/expressions.md b/docs/source/user-guide/expressions.md
@@ -234,6 +234,7 @@ Unlike to some databases the math functions in Datafusion works the same way as
 | array_to_string(array, delimiter)     | Converts each element to its text representation. `array_to_string([1, 2, 3, 4], ',') -> 1,2,3,4`                                                                        |
 | array_intersect(array1, array2)       | Returns an array of the elements in the intersection of array1 and array2. `array_intersect([1, 2, 3, 4], [5, 6, 3, 4]) -> [3, 4]`                                       |
 | array_union(array1, array2)           | Returns an array of the elements in the union of array1 and array2 without duplicates. `array_union([1, 2, 3, 4], [5, 6, 3, 4]) -> [1, 2, 3, 4, 5, 6]`                   |
+| array_except(array1, array2)          | Returns an array of the elements that appear in the first array but not in the second. `array_except([1, 2, 3, 4], [5, 6, 3, 4]) -> [3, 4]`                              |
 | cardinality(array)                    | Returns the total number of elements in the array. `cardinality([[1, 2, 3], [4, 5, 6]]) -> 6`                                                                            |
 | make_array(value1, [value2 [, ...]])  | Returns an Arrow array using the specified input expressions. `make_array(1, 2, 3) -> [1, 2, 3]`                                                                         |
 | range(start [, stop, step])           | Returns an Arrow array between start and stop with step. `SELECT range(2, 10, 3) -> [2, 5, 8]`                                                                           |

diff --git a/docs/source/user-guide/sql/scalar_functions.md b/docs/source/user-guide/sql/scalar_functions.md
@@ -2267,6 +2267,44 @@ array_union(array1, array2)
 
 - list_union
 
+### `array_except`
+
+Returns an array of the elements that appear in the first array but not in the second.
+
+```
+array_except(array1, array2)
+```
+
+#### Arguments
+
+- **array1**: Array expression.
+  Can be a constant, column, or function, and any combination of array operators.
+- **array2**: Array expression.
+  Can be a constant, column, or function, and any combination of array operators.
+
+#### Example
+
+```
+❯ select array_except([1, 2, 3, 4], [5, 6, 3, 4]);
++----------------------------------------------------+
+| array_union([1, 2, 3, 4], [5, 6, 3, 4]);           |
++----------------------------------------------------+
+| [1, 2]                                 |
++----------------------------------------------------+
+❯ select array_union([1, 2, 3, 4], [3, 4, 5, 6]);
++----------------------------------------------------+
+| array_union([1, 2, 3, 4], [3, 4, 5, 6]);           |
++----------------------------------------------------+
+| [3, 4]                                 |
++----------------------------------------------------+
+```
+
+---
+
+#### Aliases
+
+- list_except
+
 ### `cardinality`
 
 Returns the total number of elements in the array.