ARRAY_MAP
array_map
array_map(lambda,array1,array2....)
description
Syntax
ARRAY<T> array_map(lambda, ARRAY<T> array1, ARRAY<T> array2)
使用一个lambda表达式作为输入参数，对其他的输入ARRAY参数的内部数据做对应表达式计算。 在lambda表达式中输入的参数为1个或多个，必须和后面的输入array列数量一致。 在lambda中可以执行合法的标量函数，不支持聚合函数等。
array_map(x->x, array1);
array_map(x->(x+2), array1);
array_map(x->(abs(x)-2), array1);
array_map((x,y)->(x = y), array1, array2);
array_map((x,y)->(power(x,2)+y), array1, array2);
array_map((x,y,z)->(abs(x)+y*z), array1, array2, array3);
example
mysql [test]>select *, array_map(x->x,[1,2,3]) from array_test2 order by id;
+------+-----------------+-------------------------+----------------------------------------+
| id | c_array1 | c_array2 | array_map([x] -> x(0), ARRAY(1, 2, 3)) |
+------+-----------------+-------------------------+----------------------------------------+
| 1 | [1, 2, 3, 4, 5] | [10, 20, -40, 80, -100] | [1, 2, 3] |
| 2 | [6, 7, 8] | [10, 12, 13] | [1, 2, 3] |
| 3 | [1] | [-100] | [1, 2, 3] |
| 4 | NULL | NULL | [1, 2, 3] |
+------+-----------------+-------------------------+----------------------------------------+
4 rows in set (0.02 sec)
mysql [test]>select *, array_map(x->x+2,[1,2,3]) from array_test2 order by id;
+------+-----------------+-------------------------+--------------------------------------------+
| id | c_array1 | c_array2 | array_map([x] -> x(0) + 2, ARRAY(1, 2, 3)) |
+------+-----------------+-------------------------+--------------------------------------------+
| 1 | [1, 2, 3, 4, 5] | [10, 20, -40, 80, -100] | [3, 4, 5] |
| 2 | [6, 7, 8] | [10, 12, 13] | [3, 4, 5] |
| 3 | [1] | [-100] | [3, 4, 5] |
| 4 | NULL | NULL | [3, 4, 5] |
+------+-----------------+-------------------------+--------------------------------------------+
4 rows in set (0.02 sec)
mysql [test]>select c_array1, c_array2, array_map(x->x,[1,2,3]) from array_test2 order by id;
+-----------------+-------------------------+----------------------------------------+
| c_array1 | c_array2 | array_map([x] -> x(0), ARRAY(1, 2, 3)) |
+-----------------+-------------------------+----------------------------------------+
| [1, 2, 3, 4, 5] | [10, 20, -40, 80, -100] | [1, 2, 3] |
| [6, 7, 8] | [10, 12, 13] | [1, 2, 3] |
| [1] | [-100] | [1, 2, 3] |
| NULL | NULL | [1, 2, 3] |
+-----------------+-------------------------+----------------------------------------+
4 rows in set (0.01 sec)
mysql [test]>select c_array1, c_array2, array_map(x->power(x,2),[1,2,3]) from array_test2 order by id;
+-----------------+-------------------------+----------------------------------------------------+
| c_array1 | c_array2 | array_map([x] -> power(x(0), 2.0), ARRAY(1, 2, 3)) |
+-----------------+-------------------------+----------------------------------------------------+
| [1, 2, 3, 4, 5] | [10, 20, -40, 80, -100] | [1, 4, 9] |
| [6, 7, 8] | [10, 12, 13] | [1, 4, 9] |
| [1] | [-100] | [1, 4, 9] |
| NULL | NULL | [1, 4, 9] |
+-----------------+-------------------------+----------------------------------------------------+
mysql [test]>select c_array1, c_array2, array_map((x,y)->x+y,c_array1,c_array2) from array_test2 order by id;
+-----------------+-------------------------+----------------------------------------------------------+
| c_array1 | c_array2 | array_map([x, y] -> x(0) + y(1), `c_array1`, `c_array2`) |
+-----------------+-------------------------+----------------------------------------------------------+
| [1, 2, 3, 4, 5] | [10, 20, -40, 80, -100] | [11, 22, -37, 84, -95] |
| [6, 7, 8] | [10, 12, 13] | [16, 19, 21] |
| [1] | [-100] | [-99] |
| NULL | NULL | NULL |
+-----------------+-------------------------+----------------------------------------------------------+
4 rows in set (0.02 sec)
mysql [test]>select c_array1, c_array2, array_map((x,y)->power(x,2)+y,c_array1, c_array2) from array_test2 order by id;
+-----------------+-------------------------+----------------------------------------------------------------------+
| c_array1 | c_array2 | array_map([x, y] -> power(x(0), 2.0) + y(1), `c_array1`, `c_array2`) |
+-----------------+-------------------------+----------------------------------------------------------------------+
| [1, 2, 3, 4, 5] | [10, 20, -40, 80, -100] | [11, 24, -31, 96, -75] |
| [6, 7, 8] | [10, 12, 13] | [46, 61, 77] |
| [1] | [-100] | [-99] |
| NULL | NULL | NULL |
+-----------------+-------------------------+----------------------------------------------------------------------+
4 rows in set (0.03 sec)
mysql [test]>select *,array_map(x->x=3,c_array1) from array_test2 order by id;
+------+-----------------+-------------------------+----------------------------------------+
| id | c_array1 | c_array2 | array_map([x] -> x(0) = 3, `c_array1`) |
+------+-----------------+-------------------------+----------------------------------------+
| 1 | [1, 2, 3, 4, 5] | [10, 20, -40, 80, -100] | [0, 0, 1, 0, 0] |
| 2 | [6, 7, 8] | [10, 12, 13] | [0, 0, 0] |
| 3 | [1] | [-100] | [0] |
| 4 | NULL | NULL | NULL |
+------+-----------------+-------------------------+----------------------------------------+
4 rows in set (0.02 sec)
mysql [test]>select *,array_map(x->x>3,c_array1) from array_test2 order by id;
+------+-----------------+-------------------------+----------------------------------------+
| id | c_array1 | c_array2 | array_map([x] -> x(0) > 3, `c_array1`) |
+------+-----------------+-------------------------+----------------------------------------+
| 1 | [1, 2, 3, 4, 5] | [10, 20, -40, 80, -100] | [0, 0, 0, 1, 1] |
| 2 | [6, 7, 8] | [10, 12, 13] | [1, 1, 1] |
| 3 | [1] | [-100] | [0] |
| 4 | NULL | NULL | NULL |
+------+-----------------+-------------------------+----------------------------------------+
4 rows in set (0.02 sec)
mysql [test]>select *,array_map((x,y)->x>y,c_array1,c_array2) from array_test2 order by id;
+------+-----------------+-------------------------+----------------------------------------------------------+
| id | c_array1 | c_array2 | array_map([x, y] -> x(0) > y(1), `c_array1`, `c_array2`) |
+------+-----------------+-------------------------+----------------------------------------------------------+
| 1 | [1, 2, 3, 4, 5] | [10, 20, -40, 80, -100] | [0, 0, 1, 0, 1] |
| 2 | [6, 7, 8] | [10, 12, 13] | [0, 0, 0] |
| 3 | [1] | [-100] | [1] |
| 4 | NULL | NULL | NULL |
+------+-----------------+-------------------------+----------------------------------------------------------+
4 rows in set (0.02 sec)
mysql [test]>select array_map(x->cast(x as string), c_array1) from test_array_map_function;
+-----------------+-------------------------------------------------------+
| c_array1 | array_map([x] -> CAST(x(0) AS CHARACTER), `c_array1`) |
+-----------------+-------------------------------------------------------+
| [1, 2, 3, 4, 5] | ['1', '2', '3', '4', '5'] |
| [6, 7, 8] | ['6', '7', '8'] |
| [] | [] |
| NULL | NULL |
+-----------------+-------------------------------------------------------+
4 rows in set (0.01 sec)
keywords
ARRAY,MAP,ARRAY_MAP
