[KYLIN-5359] Kylin4 replace function expression convert error

• Type: Bug
• Status: In Progress
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: v4.0.1, v4.0.2
• Component/s: Query Engine
• Assignee: Liu Zhao
• Reporter: Liu Zhao
• Created: 12/Dec/22 03:26
• Updated: 27/Dec/22 05:52

Description

查询语句形如：select name, replace(name, substring(name, 1, 1), '--') as new_name from LZ_TEST_YUFA 执行出错
errorMsg：java.lang.ClassCastException: org.apache.spark.sql.Column cannot be cast to java.lang.String while executing SQL: "select * from (select name, replace(name, substring(name, 1, 1), '--') as new_name from LZ_TEST_YUFA) limit 50000

原因：在ExpressionConverter中subtring返回的是一个column对象，而在replace转换中强制将函数参数转换为string

// ExpressionConverter
case "replace " =>
	regexp_replace(k_lit(children.head),
	  {color:red}children.apply(1).asInstanceOf[String],
	  children.apply(2).asInstanceOf[String]{color})
case "substring" | "substr" =>
	if (children.length == 3) { //substr(str1,startPos,length)
	 {color:red} k_lit(children.head)
		.substr(k_lit(children.apply(1)), k_lit(children.apply(2))){color}
	} else if (children.length == 2) { //substr(str1,startPos)
	  k_lit(children.head).
		substr(k_lit(children.apply(1)), k_lit(Int.MaxValue))
	} else {
	  throw new UnsupportedOperationException(
		s"substring must provide three or two parameters under sparder")
	}
case "initcapb" =>
	initcap(k_lit(children.head))