问在spark.sql中的select中使用cast()EN$cast可以对不同的内建类型进行转换，用的更多的是不同层次之...
1.SELECT CAST('9.0' AS decimal) 结果:9 2.SELECT CAST('9.5' AS decimal(10,2))结果:9.50 注:(精度与小数位数分别为10与2。精度是总的数字位数,包括小数点左边和右边位数的总和。而小数位数是小数点右边的位数) 3.SELECT CAST(NOW() AS DATE)结果:2017-11-27...
valdf=spark.range(5).selectExpr("id","cast(id as double) as value")df.show()df.selectExpr("id","round(value, 0) as rounded_value").show() 1. 2. 3. 4. 输出结果如下: AI检测代码解析 +---+---+ | id|value| +---+---+ | 0| 0.0| | 1| 1.0| | 2| 2.0| | 3| 3.0|...
代码语言:txt 复制 import org.apache.spark.sql.functions._ val df = spark.read.format("csv").load("data.csv") // 从CSV文件中加载数据 val intCol = df("str_col").cast("integer") // 将字符串列转换为整数列 在上述代码中,cast函数将str_col列转换为整数类型,并将结果赋值给intCo...
- cast('12.5' as decimal) 结果是:12 精度和小数位数默认值分别是18与0。如果在decimal类型中不提供这两个值,将截断小数部分,并不会像第二个例子一样报错。 三、数学运算 round 四舍五入 floor 取左值 ceil 取右值 例子: select round(1.2356); +---+ |round(1.2356, 0)| +---+ | 1| +---+...
// Note that we add a cast to non-predicate expressions. If the expression itself is // already boolean, the optimizer will get rid of the unnecessary cast. val predicate = expression(having) match { case p: Predicate => p case e => Cast(e, BooleanType) } Filter(predicate, withProje...
then concat( '0' , cast( month(current_date) as string) ) else month(current_date) end ) as month, day(current_date) as day, ( case length(hour(current_timestamp)) when 1 then concat( '0' , cast ( hour(current_timestamp) as string) ) ...
2 + 3) AS DOUBLE))#325, value#324]+- Join Inner,((key#321 = key#323) && (cast(key#321 as double) > cast(3 as double))):- SubqueryAlias a :+- MetastoreRelation default, t +- SubqueryAlias b +- MetastoreRelation default, t== Optimized Logical Plan ==Project [(cast(...
SimplifyCasts:Cast简化 SimplifyCaseConversionExpressions:CASE大小写转化表达式简化 Filter Pushdown Filter下推 CombineFilters Filter合并 PushPredicateThroughProject:通过Project下推 PushPredicateThroughJoin:通过Join下推 ColumnPruning:列剪枝 搜索『后端精进之路』并关注,立刻获取文章合集和面试攻略,还有价值数千元的面试...
使用SparkSQL的cast函数或通过在读取数据时指定数据类型来解决数据类型不匹配的问题。 9、日期格式不一致 日期格式错误会导致日期解析失败: 确认Spark SQL配置文件中的日期格式是否与数据文件中的日期格式一致。 使用SparkSQL的to_date函数或DateFormatter类指定正确的日期格式。