ARRAY_LAST_INDEX
array_last_index
array_last_index
description
Syntax
ARRAY<T> array_last_index(lambda, ARRAY<T> array1, ...)
使用 lambda 表达式作为输入参数，对其他输入 ARRAY 参数的内部数据进行相应的表达式计算。返回最后一个使得 lambda(array1[i], ...) 返回值不为 0 的索引。如果没找到满足此条件的索引，则返回 0。
在 lambda 表达式中输入的参数为 1 个或多个，所有输入的 array 的元素数量必须一致。在 lambda 中可以执行合法的标量函数，不支持聚合函数等。
array_last_index(x->x>1, array1);
array_last_index(x->(x%2 = 0), array1);
array_last_index(x->(abs(x)-1), array1);
array_last_index((x,y)->(x = y), array1, array2);
example
mysql> select array_last_index(x->x+1>3, [2, 3, 4]);
+-------------------------------------------------------------------+
| array_last_index(array_map([x] -> x(0) + 1 > 3, ARRAY(2, 3, 4))) |
+-------------------------------------------------------------------+
| 3 |
+-------------------------------------------------------------------+
mysql> select array_last_index(x -> x is null, [null, 1, 2]);
+----------------------------------------------------------------------+
| array_last_index(array_map([x] -> x(0) IS NULL, ARRAY(NULL, 1, 2))) |
+----------------------------------------------------------------------+
| 1 |
+----------------------------------------------------------------------+
mysql> select array_last_index(x->power(x,2)>10, [1, 2, 3, 4]);
+---------------------------------------------------------------------------------+
| array_last_index(array_map([x] -> power(x(0), 2.0) > 10.0, ARRAY(1, 2, 3, 4))) |
+---------------------------------------------------------------------------------+
| 4 |
+---------------------------------------------------------------------------------+
mysql> select c_array1, c_array2, array_last_index((x,y)->x>y, c_array1, c_array2) from array_index_table order by id;
+-----------------+-------------------------+----------------------------------------------------------------------+
| c_array1 | c_array2 | array_last_index(array_map([x, y] -> x > y, `c_array1`, `c_array2`)) |
+-----------------+-------------------------+----------------------------------------------------------------------+
| [1, 2, 3, 4, 5] | [10, 20, -40, 80, -100] | 5 |
| [6, 7, 8] | [10, 12, 13] | 0 |
| [1] | [-100] | 1 |
| [1, NULL, 2] | [NULL, 3, 1] | 3 |
| [] | [] | 0 |
| NULL | NULL | 0 |
+-----------------+-------------------------+----------------------------------------------------------------------+
keywords
ARRAY,FIRST_INDEX,array_last_index
