SQL split

在 SQL 中，可以使用内置函数 `SUBSTRING_INDEX()` 来拆分字符串。`SUBSTRING_INDEX(str, delim, count)` 函数将会返回从左边开始第 `count` 个分隔符 `delim` 之前或之后的子字符串 `str`。例如，以下 SQL 查询将会从表 `example` 的 `column` 列中获取以逗号 `,` 分隔的第一个子字符串：

SELECT SUBSTRING_INDEX(column, ',', 1) FROM example;

如果要获取第二个子字符串，只需将 `count` 参数设置为 `2`。如果要获取最后一个子字符串，则将 `count` 参数设置为 `-1`。

相关问题

saprk sql split

Spark SQL Split function is used to split a string into an array of substrings based on a specified delimiter. The syntax for split function in Spark SQL is as follows:

split(string, delimiter)

Where,
- `string` is the input string that needs to be split.
- `delimiter` is the character or string used as a separator to split the input string.

For example, if we have a string "Hello,World" and we want to split it into an array of substrings based on the comma separator, we can use the split function as follows:

SELECT split("Hello,World", ",") as words

This will return an array of two strings - "Hello" and "World".

We can also use the split function with column names in a table to split the values in that column. For example, if we have a table `employee` with a column `name` containing full names separated by spaces, we can split the names into first and last name using the split function as follows:

SELECT split(name, " ")[0] as first_name, split(name, " ")[1] as last_name FROM employee

This will return a table with two columns - `first_name` and `last_name` containing the first and last names of all employees in the `employee` table.

spark sql split

在Spark SQL中，可以使用split函数来分割字符串。split函数接受两个参数：要分割的字符串和分隔符。

下面是一个示例代码，展示如何在Spark SQL中使用split函数进行字符串分割：

import org.apache.spark.sql.functions._

// 创建一个DataFrame
val data = Seq(("John,Doe"), ("Jane,Smith"), ("Tom,Hanks"))
val df = spark.createDataFrame(data).toDF("name")

// 使用split函数分割字符串
val splitDF = df.select(split(col("name"), ",").as("split_name"))

// 展示分割后的结果
splitDF.show()

运行以上代码，会得到以下输出：

+----------+
|split_name|
+----------+
| [John, Doe]|
|[Jane, Smith]|
| [Tom, Hanks]|
+----------+

在上面的示例中，我们使用split函数将"name"列中的字符串按照逗号进行分割，并将结果存储在新的列"split_name"中。你可以根据实际需求修改代码来适应你的数据。