中文解释下这个sql，explode(split(substr(plan_ids, 2, length(plan_ids) -2), ',')) as plan_id

这个SQL语句的作用是将一个字符串类型的plan_ids字段，去掉首尾的括号（substring），然后按照逗号分隔符（split）分开，再将每个分隔出来的子串作为一行数据（explode），并将这些子串作为新的plan_id列返回。

具体地说，这个SQL语句的执行过程如下：

1. substr(plan_ids, 2, length(plan_ids) -2)：截取plan_ids字段的第2个字符到倒数第2个字符之间的子串，去掉首尾的括号。

2. split(substr(plan_ids, 2, length(plan_ids) -2), ',')：将上一步得到的子串按照逗号分隔符进行分割，得到一个数组。

3. explode(split(substr(plan_ids, 2, length(plan_ids) -2), ','))：将上一步得到的数组转换成多行数据，每个子串作为新的plan_id列的一行数据。

4. as plan_id：将上一步得到的新列命名为plan_id。

相关问题

explode(split(substr(plan_ids, 2, length(plan_ids) -2), ',')) as plan_id

I'm sorry, as an AI language model, I cannot provide any context for the code snippet you have provided. However, I can explain the functionality of the code.

The code appears to be written in SQL and uses the following functions:

1. `substr`: This function is used to extract a substring from a string. In this case, it is used to extract a portion of the string `plan_ids`.

2. `length`: This function returns the length of a string. It is used here to calculate the length of the string `plan_ids`.

3. `split`: This function is used to split a string into an array of substrings based on a delimiter. Here, the delimiter is a comma.

4. `explode`: This function is used to convert an array of strings into individual rows. In this case, it is used to convert the array of plan IDs into individual rows.

Finally, the `as` keyword is used to assign an alias to the resulting column, which is `plan_id` in this case.

讲hive的lateral view explode(split(array_concat,','))改成presto可用的函数

在 Presto 中，我们可以使用 `UNNEST` 函数来展开数组。因此，可以将 `lateral view explode(split(array_concat,','))` 改写为：

SELECT *
FROM my_table
CROSS JOIN UNNEST(SPLIT(array_concat, ',')) AS my_column

这将会将 `array_concat` 字段中的数组展开，并将其存储在名为 `my_column` 的列中，以便后续处理。