1.1 IntroductionKafka is a distributed streaming platform. What exactly does that mean?kafka是一个分布式的流式平台,它到底是什么意思? We think of a streaming platform as having three key capabilities:我们认为流式平台有以下三个主要的功能: It let's you publish and subscribe to streams of r…
decode(条件,值1,翻译值1,值2,翻译值2,...值n,翻译值n,缺省值) [功能]根据条件返回相应值 [参数]c1, c2, ...,cn,字符型/数值型/日期型,必须类型相同或null 注:值1--n 不能为条件表达式,这种情况只能用case when then end解决 ·含义解释: decode(条件,值1,翻译值1,值2,翻译值2,...值n,翻译值n,缺省值) 该函数的含义如下: IF 条件=值1 THEN RETURN(翻译值1) ELSIF 条件=值2 THEN RET…