WebGreenPlum中正则表达式的支持非常灵活，支持正则表达式操作符，而在GBase中是不支持的，但是所有的这些操作符都可以使用GBase提供的REGEXP进行替换。此外，GreenPlum和GBase均实现了常见的正则表达式函数，例如regexp_replace函数，可以将模式匹配的字符串替换成指定 ... Web从传统数据库迁移到GP中一个重要的且常常被开发者忽略的概念是数据分布，没有良好的设计表的分布键会导致严重的性能问题。下面函数将给开发者及DBA检測一个表的数据倾斜情况。--Function:gpmg.data_skew(charactervarying)--DROPFUNCTIONgpmg.data_skew(charactervarying);CREATEORREPLACEFUNCTIONgpm

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WebArray_agg: This function in PostgreSQL works same as group_concat function which was used in other database. This function is basically used to return the element from group of array. This function is very important in PostgreSQL to concatenate the column values. Value separator: This is defined as separate column value by using the separator ... WebGreenplum数据库的GROUP BY扩展可以执行某些常用的计算，且比应用程序或者存储过程效率高。 GROUP BY ROLLUP (col1, col2, col3) GROUP BY CUBE (col1, col2, col3) GROUP BY GROUPING SETS ( (col1, col2), (col1, col3)) ROLLUP 对分组字段（或者表达式）从最详细级别到最顶级别计算聚合计数。 ROLLUP的参数是一个有序分组字段列 … how befriend a crow

GPDB 7 when use grouping sets like rollup, will first …

WebJul 18, 2013 · GROUP BY ROLLUP(x_GRP)) ORDER BY x_GRP---It results exactly as I expected. X_GRP CNT_CUST DIST 1. Non-Missing 12345 15.43% 2.Missing 67640 … WebGreenplum Database has the following additional OLAP grouping extensions (often referred to as supergroups): ROLLUP A ROLLUP grouping is an extension to the GROUP BY … how be funny