SSparkSQLS parkSQ parkSQLS SSparkSQ 补足函数:lpad \ rpad lpad(str, len[, pad]) - Returns str, left-padded with pad to a length of len. If str is longer than len, the return value is shortened to len characters or bytes. If pad is not specified, str will be padded to the lef...
def main(args: Array[String]) { if (args.length != 3) { System.err.println("Usage: <filename> <port> <millisecond>") System.exit(1) } val fileName = args(0) val lines = Source.fromFile(fileName).getLines.toList val rowCount = lines.length val listener = new ServerSocket(args(...
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select decode(encode("HIVE", "UTF-8"), "UTF-8"); 5. format_string / printf 格式化字符串:format_string(strfmt, obj, ...) -- returns a formatted string from printf-style format strings select format_string("Spark SQL %d %s", 100, "days"); 6. initcap / lower / upper initcap:将...
initcap(str) - Returnsstrwith the first letter of each word in uppercase. All other letters are in lowercase. Words are delimited by white space. Examples:> SELECT initcap('sPark sql');Spark Sql 7.length返回字符串的长度 Examples:> SELECT length('Spark SQL ');10 ...
length(string1):返回字符串长度 concat(string1,string2):返回拼接string1及string2后的字符串 concat_ws(sep,string1,string2):返回按指定分隔符拼接的字符串 lower(string1):返回小写字符串,同lcase(string1)。upper()/ucase():返回大写字符串 trim(string1):去字符串左右空格,ltrim(string1):去字符串左空...
1.谈谈你对Spark SQL的理解 SparkSQL是一个用来处理结构化数据的Spark组件,前身是shark,但是shark过多的依赖于hive如采用hive的语法解析器、查询优化器等,制约了Spark各个组件之间的相互集成,因此Spark SQL应运而生。 Spark SQL在汲取了shark诸多优势如内存列存储、兼容hive等基础上,做了重新的构造,因此也摆脱了对hi...
Footer length 存储了文件元数据的大小,通过该值和文件长度可以计算出元数据的偏移量,文件的元数据中包括每一个行组的元数据信息和当前文件的 Schema 信息。 每一页的开始都会存储该页的元数据,在 Parquet 中,有三种类型的页:数据页、字典页和索引页。数据页用于存储当前行组中该列的值,字典页存储该列值的编码...
This document introduces the syntax of the string functions in Spark SQL. String Character Count You are advised to use LEN in New Calculation Column of FineDatalink. CHAR_LENGTH(String): Returns the number of characters in the string. CHARACTER_LENGTH(String): Returns the number of characters...
1importorg.apache.spark.SparkConf2importorg.apache.spark.SparkContext3importorg.apache.spark.sql.SQLContext4importorg.apache.spark.sql.hive.HiveContext56object Test {7def main(args: Array[String]): Unit ={8val conf =newSparkConf().setAppName("Test")9val sc =newSparkContext(conf)10val sql...