用户自定义函数(UDF)是一种允许用户在 Spark SQL 中定义自己的函数并应用于 DataFrame 的功能。UDF 可以接受一个或多个输入参数,并生成一个输出结果。UDF 的目的是扩展 Spark SQL 的功能,使用户能够使用自定义逻辑对数据进行处理和转换。 在Apache Spark 中,UDF 的原理是通过创建UserDefinedFunction 对象来表示用户...
命名空間: Microsoft.Spark.Sql.Catalog 組件: Microsoft.Spark.dll 套件: Microsoft.Spark v1.0.0 多載展開表格 FunctionExists(String) 檢查具有指定名稱的函式是否存在。 FunctionsExists 包含內建函式,例如 abs。 若要查看內建函式是否存在,您必須使用不合格的名稱。 如果您建立函式,您可以使用限定名稱。
-- Describe a builtin user defined aggregate function -- Returns function name, implementing class and usage and examples. > DESCRIBE FUNCTION EXTENDED explode; Function: explode Class: org.apache.spark.sql.catalyst.expressions.Explode Usage: explode(expr) - Separates the elements of array `expr...
...//这里registry 是通过 外部类 Analyzer的构造方法传入的,在 spark 1.6 实例化如下://SQLContext : val functionRegistry: FunctionRegistry = FunctionRegistry.builtin.copy()//HiveContext : val functionRegistry: FunctionRegistry = new HiveFunctionRegistry(FunctionRegistry.builtin.copy(), this.executionHi...
…le foldable expressions ### What changes were proposed in this pull request? Spark SQL exists a bug show below: ``` spark.sql( " SELECT COUNT(DISTINCT 2), COUNT(DISTINCT 2, 3)") .show() +---+---+ |count(DISTINCT 2)|count(DISTINCT 2, 3)| +---+---+ | 1| 1| +-...
Learn the syntax of the read_kinesis function of the SQL language in Databricks SQL and Databricks Runtime.
columnNameOfCorruptRecord (default is the value specified in spark.sql.columnNameOfCorruptRecord): allows renaming the new field having malformed string created by PERMISSIVE mode. This overrides spark.sql.columnNameOfCorruptRecord. dateFormat (default yyyy-MM-dd): sets the string that indicates...
object SparkUdfInSqlBasicUsageStudy { def main(args: Array[String]): Unit = { val spark = SparkSession.builder().master("local[*]").appName("SparkUdfStudy").getOrCreate() import spark.implicits._ // 注册可以在sql语句中使用的UDF ...
(See the SQL_DRIVER_HDESC or SQL_DRIVER_HSTMT descriptors later in this function description for more information.)If InfoValuePtr is NULL, StringLengthPtr will still return the total number of bytes (excluding the null-termination character for character data) available to return in the buffer...
(See the SQL_DRIVER_HDESC or SQL_DRIVER_HSTMT descriptors later in this function description for more information.)If InfoValuePtr is NULL, StringLengthPtr will still return the total number of bytes (excluding the null-termination character for character data) available to return in the buffer...