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c5718928df
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[feature-wip](array-type) support explode and explode_outer table function (#8766)
explode(ArrayColumn) desc:
> Create a row for each element in the array column.
explode_outer(ArrayColumn) desc:
> Create a row for each element in the array column. Unlike explode, if the array is null or empty, it returns null.
Usage example:
1. create a table with array column, and insert some data;
2. open enable_lateral_view and enable_vectorized_engine;
```
set enable_lateral_view = true;
set enable_vectorized_engine=true;
```
3. use explode_outer
```
> select * from array_test;
+------+------+--------+
| k1 | k2 | k3 |
+------+------+--------+
| 3 | NULL | NULL |
| 1 | 2 | [1, 2] |
| 2 | 3 | NULL |
| 4 | NULL | [] |
+------+------+--------+
> select k1,explode_column from array_test LATERAL VIEW explode_outer(k3) TempExplodeView as explode_column;
+------+----------------+
| k1 | explode_column |
+------+----------------+
| 1 | 1 |
| 1 | 2 |
| 2 | NULL |
| 4 | NULL |
| 3 | NULL |
+------+----------------+
```
4. explode usage example. explode return empty rows while the ARRAY is null or empty
```
> select k1,explode_column from array_test LATERAL VIEW explode(k3) TempExplodeView as explode_column;
+------+----------------+
| k1 | explode_column |
+------+----------------+
| 1 | 1 |
| 1 | 2 |
+------+----------------+
```
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2022-04-08 12:11:04 +08:00 |
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