spark-sql-ParserInterface.adoc

ParserInterface — SQL Parser Contract

ParserInterface is the parser contract for creating Expression (to create Columns from), LogicalPlan, TableIdentifier, and StructType for the textual representation of a SQL statement.

Note	The one and only ParserInterface in Spark SQL is AbstractSqlParser.

ParserInterface is available as sqlParser in SessionState.

val spark: org.apache.spark.sql.SparkSession = ...
spark.sessionState.sqlParser

ParserInterface Contract

package org.apache.spark.sql.catalyst.parser

trait ParserInterface {
  def parseExpression(sqlText: String): Expression
  def parsePlan(sqlText: String): LogicalPlan
  def parseTableIdentifier(sqlText: String): TableIdentifier
  def parseTableSchema(sqlText: String): StructType
}

Table 1. ParserInterface Contract

Method	Description
parseExpression	Used when…​
parsePlan	Used mainly when SparkSession is requested to execute a SQL query using sql method. scala> :type spark org.apache.spark.sql.SparkSession scala> spark.sql("show databases").show +------------+ |databaseName| +------------+ | default| +------------+
parseTableIdentifier	Used when…​
parseTableSchema	Used when…​