出现“error while compiling statement: failed: semanticexception cartesian”错误通常意味着在执行SQL查询时发生了笛卡尔积(Cartesian product)错误。笛卡尔积错误发生在没有明确定义两个表之间如何关联的情况下,导致数据库尝试生成两个表的所有可能组合,这通常会导致性能问题和不期望的结果。以下是针对此错误的详细解答: ...
Cartesian product(笛卡尔积)是数学和计算机科学中的一个基础概念,指两个或多个集合中所有可能有序组合的集合。其核心思想是通
Generally speaking, a Cartesian SQL product generates a large number of lines and the result is rarely useful. Therefore, when you work with SQL tables, it is better to avoid Cartesian product usage. You should always include a valid JOIN condition in the WHERE clause, except for the cases ...
SQL Cartesian product optimization Posted 11-21-2011 03:11 AM (4809 views) | In reply to BruceBrad You can try it. But I am not sure whether this code will be faster. NOT TESTED proc sql; create table want as select a.id as id,(select count(*) from test as b where geodist(...
SparkSql运行程序报错, Exception in thread "main" org.apache.spark.sql.AnalysisException: Detected cartesian product for INNER join between logical plans 解决方式:设置spark.sql.crossJoin.enabled=true 因为,2.x中默认不支持笛卡尔积操作,需要通过参数spark.sql.crossJoin.enabled开启 ...
但是仔细分析笛卡尔积源码,就会发现,它的运行原理是这样的: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 select tmp1.a,tmp2.b from testdata2 tmp1 join testdata2 tmp2==executedPlan==CartesianProduct:-SerializeFromObject[knownnotnull(assertnotnull(input[0,org.apache.spark.sql.test.SQLTestData...
如确认需要使用笛卡尔积，可以任务级别set odps.sql.allow.cartesian=true;与sql一同运行。
1) Cartesian product is also called Set multiple. 2) Cartesian product is actually a total combination of the two sets. Q: Let set A have M elements which are unique in set A; Let set B have N elements which are unique in set B. So how many element will we get after cartesian pro...
Spark的功能涵盖了大数据领域的离线批处理、SQL类处理、流式/实时计算、机器学习、图计算等各种不同类型...
a,tmp2.b from testdata2 tmp1 join testdata2 tmp2 == executedPlan == CartesianProduct :- SerializeFromObject [knownnotnull(assertnotnull(input[0, org.apache.spark.sql.test.SQLTestData$TestData2, true])).a AS a#3] : +- Scan[obj#2] +- SerializeFromObject [knownnotnull(assert...