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author | Wenchen Fan <cloud0fan@163.com> | 2014-09-10 12:56:59 -0700 |
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committer | Michael Armbrust <michael@databricks.com> | 2014-09-10 12:56:59 -0700 |
commit | e4f4886d7148bf48f9e3462b83bfb1ecc7edbe31 (patch) | |
tree | ef2eb99181260a633e898c6476475b26086e0c80 /sql/catalyst/src | |
parent | 1f4a648d4e30e837d6cf3ea8de1808e2254ad70b (diff) | |
download | spark-e4f4886d7148bf48f9e3462b83bfb1ecc7edbe31.tar.gz spark-e4f4886d7148bf48f9e3462b83bfb1ecc7edbe31.tar.bz2 spark-e4f4886d7148bf48f9e3462b83bfb1ecc7edbe31.zip |
[SPARK-2096][SQL] Correctly parse dot notations
First let me write down the current `projections` grammar of spark sql:
expression : orExpression
orExpression : andExpression {"or" andExpression}
andExpression : comparisonExpression {"and" comparisonExpression}
comparisonExpression : termExpression | termExpression "=" termExpression | termExpression ">" termExpression | ...
termExpression : productExpression {"+"|"-" productExpression}
productExpression : baseExpression {"*"|"/"|"%" baseExpression}
baseExpression : expression "[" expression "]" | ... | ident | ...
ident : identChar {identChar | digit} | delimiters | ...
identChar : letter | "_" | "."
delimiters : "," | ";" | "(" | ")" | "[" | "]" | ...
projection : expression [["AS"] ident]
projections : projection { "," projection}
For something like `a.b.c[1]`, it will be parsed as:
<img src="http://img51.imgspice.com/i/03008/4iltjsnqgmtt_t.jpg" border=0>
But for something like `a[1].b`, the current grammar can't parse it correctly.
A simple solution is written in `ParquetQuerySuite#NestedSqlParser`, changed grammars are:
delimiters : "." | "," | ";" | "(" | ")" | "[" | "]" | ...
identChar : letter | "_"
baseExpression : expression "[" expression "]" | expression "." ident | ... | ident | ...
This works well, but can't cover some corner case like `select t.a.b from table as t`:
<img src="http://img51.imgspice.com/i/03008/v2iau3hoxoxg_t.jpg" border=0>
`t.a.b` parsed as `GetField(GetField(UnResolved("t"), "a"), "b")` instead of `GetField(UnResolved("t.a"), "b")` using this new grammar.
However, we can't resolve `t` as it's not a filed, but the whole table.(if we could do this, then `select t from table as t` is legal, which is unexpected)
My solution is:
dotExpressionHeader : ident "." ident
baseExpression : expression "[" expression "]" | expression "." ident | ... | dotExpressionHeader | ident | ...
I passed all test cases under sql locally and add a more complex case.
"arrayOfStruct.field1 to access all values of field1" is not supported yet. Since this PR has changed a lot of code, I will open another PR for it.
I'm not familiar with the latter optimize phase, please correct me if I missed something.
Author: Wenchen Fan <cloud0fan@163.com>
Author: Michael Armbrust <michael@databricks.com>
Closes #2230 from cloud-fan/dot and squashes the following commits:
e1a8898 [Wenchen Fan] remove support for arbitrary nested arrays
ee8a724 [Wenchen Fan] rollback LogicalPlan, support dot operation on nested array type
a58df40 [Michael Armbrust] add regression test for doubly nested data
16bc4c6 [Wenchen Fan] some enhance
95d733f [Wenchen Fan] split long line
dc31698 [Wenchen Fan] SPARK-2096 Correctly parse dot notations
Diffstat (limited to 'sql/catalyst/src')
-rwxr-xr-x | sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/SqlParser.scala | 13 | ||||
-rw-r--r-- | sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/LogicalPlan.scala | 6 |
2 files changed, 12 insertions, 7 deletions
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/SqlParser.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/SqlParser.scala index a04b4a938d..ca69531c69 100755 --- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/SqlParser.scala +++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/SqlParser.scala @@ -357,16 +357,25 @@ class SqlParser extends StandardTokenParsers with PackratParsers { expression ~ "[" ~ expression <~ "]" ^^ { case base ~ _ ~ ordinal => GetItem(base, ordinal) } | + (expression <~ ".") ~ ident ^^ { + case base ~ fieldName => GetField(base, fieldName) + } | TRUE ^^^ Literal(true, BooleanType) | FALSE ^^^ Literal(false, BooleanType) | cast | "(" ~> expression <~ ")" | function | "-" ~> literal ^^ UnaryMinus | + dotExpressionHeader | ident ^^ UnresolvedAttribute | "*" ^^^ Star(None) | literal + protected lazy val dotExpressionHeader: Parser[Expression] = + (ident <~ ".") ~ ident ~ rep("." ~> ident) ^^ { + case i1 ~ i2 ~ rest => UnresolvedAttribute(i1 + "." + i2 + rest.mkString(".", ".", "")) + } + protected lazy val dataType: Parser[DataType] = STRING ^^^ StringType | TIMESTAMP ^^^ TimestampType } @@ -380,7 +389,7 @@ class SqlLexical(val keywords: Seq[String]) extends StdLexical { delimiters += ( "@", "*", "+", "-", "<", "=", "<>", "!=", "<=", ">=", ">", "/", "(", ")", - ",", ";", "%", "{", "}", ":", "[", "]" + ",", ";", "%", "{", "}", ":", "[", "]", "." ) override lazy val token: Parser[Token] = ( @@ -401,7 +410,7 @@ class SqlLexical(val keywords: Seq[String]) extends StdLexical { | failure("illegal character") ) - override def identChar = letter | elem('_') | elem('.') + override def identChar = letter | elem('_') override def whitespace: Parser[Any] = rep( whitespaceChar diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/LogicalPlan.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/LogicalPlan.scala index f81d911194..bae491f07c 100644 --- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/LogicalPlan.scala +++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/LogicalPlan.scala @@ -104,11 +104,7 @@ abstract class LogicalPlan extends QueryPlan[LogicalPlan] { case Seq((a, Nil)) => Some(a) // One match, no nested fields, use it. // One match, but we also need to extract the requested nested field. case Seq((a, nestedFields)) => - a.dataType match { - case StructType(fields) => - Some(Alias(nestedFields.foldLeft(a: Expression)(GetField), nestedFields.last)()) - case _ => None // Don't know how to resolve these field references - } + Some(Alias(nestedFields.foldLeft(a: Expression)(GetField), nestedFields.last)()) case Seq() => None // No matches. case ambiguousReferences => throw new TreeNodeException( |