spark技术分享ParserInterface — SQL Parser Contract
ParserInterface is the contract of SQL parsers that can parse Expressions, LogicalPlans, TableIdentifiers, and StructTypes given the textual representation of SQL statements.
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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 } |
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Note
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AbstractSqlParser is the one and only known extension of the ParserInterface Contract in Spark SQL.
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ParserInterface is available as sqlParser in SessionState.
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scala> :type spark org.apache.spark.sql.SparkSession scala> :type spark.sessionState.sqlParser org.apache.spark.sql.catalyst.parser.ParserInterface |
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Parses a SQL text to an Expression Used in the following:
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Parses a SQL text to a LogicalPlan Used when:
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Used when:
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Parses a SQL text to a StructType Used when:
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