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Merged
merged 2 commits into from
Jun 10, 2019
Merged

Properly handle mixed implicit and explicit joins #109

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b841dcc
Properly handle mixed implicit and explicit joins
benesch Jun 8, 2019
ce171c2
Support VALUES and parenthesized SELECTs as top-level statements
benesch Jun 10, 2019
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2 changes: 1 addition & 1 deletion src/sqlast/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,7 @@ pub use self::ddl::{
};
pub use self::query::{
Cte, Fetch, Join, JoinConstraint, JoinOperator, SQLOrderByExpr, SQLQuery, SQLSelect,
SQLSelectItem, SQLSetExpr, SQLSetOperator, SQLValues, TableAlias, TableFactor,
SQLSelectItem, SQLSetExpr, SQLSetOperator, SQLValues, TableAlias, TableFactor, TableWithJoins,
};
pub use self::sqltype::SQLType;
pub use self::value::{SQLDateTimeField, Value};
Expand Down
42 changes: 22 additions & 20 deletions src/sqlast/query.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -113,9 +113,7 @@ pub struct SQLSelect {
/// projection expressions
pub projection: Vec<SQLSelectItem>,
/// FROM
pub relation: Option<TableFactor>,
/// JOIN
pub joins: Vec<Join>,
pub from: Vec<TableWithJoins>,
/// WHERE
pub selection: Option<ASTNode>,
/// GROUP BY
Expand All @@ -131,11 +129,8 @@ impl ToString for SQLSelect {
if self.distinct { " DISTINCT" } else { "" },
comma_separated_string(&self.projection)
);
if let Some(ref relation) = self.relation {
s += &format!(" FROM {}", relation.to_string());
}
for join in &self.joins {
s += &join.to_string();
if !self.from.is_empty() {
s += &format!(" FROM {}", comma_separated_string(&self.from));
}
if let Some(ref selection) = self.selection {
s += &format!(" WHERE {}", selection.to_string());
Expand Down Expand Up @@ -197,6 +192,22 @@ impl ToString for SQLSelectItem {
}
}

#[derive(Debug, Clone, PartialEq, Hash)]
pub struct TableWithJoins {
pub relation: TableFactor,
pub joins: Vec<Join>,
}

impl ToString for TableWithJoins {
fn to_string(&self) -> String {
let mut s = self.relation.to_string();
for join in &self.joins {
s += &join.to_string();
}
s
}
}

/// A table name or a parenthesized subquery with an optional alias
#[derive(Debug, Clone, PartialEq, Hash)]
pub enum TableFactor {
Expand All @@ -215,10 +226,7 @@ pub enum TableFactor {
subquery: Box<SQLQuery>,
alias: Option<TableAlias>,
},
NestedJoin {
base: Box<TableFactor>,
joins: Vec<Join>,
},
NestedJoin(Box<TableWithJoins>),
}

impl ToString for TableFactor {
Expand Down Expand Up @@ -257,12 +265,8 @@ impl ToString for TableFactor {
}
s
}
TableFactor::NestedJoin { base, joins } => {
let mut s = base.to_string();
for join in joins {
s += &join.to_string();
}
format!("({})", s)
TableFactor::NestedJoin(table_reference) => {
format!("({})", table_reference.to_string())
}
}
}
Expand Down Expand Up @@ -313,7 +317,6 @@ impl ToString for Join {
suffix(constraint)
),
JoinOperator::Cross => format!(" CROSS JOIN {}", self.relation.to_string()),
JoinOperator::Implicit => format!(", {}", self.relation.to_string()),
JoinOperator::LeftOuter(constraint) => format!(
" {}LEFT JOIN {}{}",
prefix(constraint),
Expand Down Expand Up @@ -342,7 +345,6 @@ pub enum JoinOperator {
LeftOuter(JoinConstraint),
RightOuter(JoinConstraint),
FullOuter(JoinConstraint),
Implicit,
Cross,
}

Expand Down
148 changes: 73 additions & 75 deletions src/sqlparser.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -109,7 +109,7 @@ impl Parser {
match self.next_token() {
Some(t) => match t {
Token::SQLWord(ref w) if w.keyword != "" => match w.keyword.as_ref() {
"SELECT" | "WITH" => {
"SELECT" | "WITH" | "VALUES" => {
self.prev_token();
Ok(SQLStatement::SQLQuery(Box::new(self.parse_query()?)))
}
Expand All @@ -133,6 +133,10 @@ impl Parser {
w.to_string()
)),
},
Token::LParen => {
self.prev_token();
Ok(SQLStatement::SQLQuery(Box::new(self.parse_query()?)))
}
unexpected => self.expected(
"a keyword at the beginning of a statement",
Some(unexpected),
Expand Down Expand Up @@ -1570,13 +1574,15 @@ impl Parser {
}
let projection = self.parse_select_list()?;

let (relation, joins) = if self.parse_keyword("FROM") {
let relation = Some(self.parse_table_factor()?);
let joins = self.parse_joins()?;
(relation, joins)
} else {
(None, vec![])
};
let mut from = vec![];
if self.parse_keyword("FROM") {
loop {
from.push(self.parse_table_and_joins()?);
if !self.consume_token(&Token::Comma) {
break;
}
}
}

let selection = if self.parse_keyword("WHERE") {
Some(self.parse_expr()?)
Expand All @@ -1599,14 +1605,69 @@ impl Parser {
Ok(SQLSelect {
distinct,
projection,
from,
selection,
relation,
joins,
group_by,
having,
})
}

pub fn parse_table_and_joins(&mut self) -> Result<TableWithJoins, ParserError> {
let relation = self.parse_table_factor()?;
let mut joins = vec![];
loop {
let join = match &self.peek_token() {
Some(Token::SQLWord(kw)) if kw.keyword == "CROSS" => {
self.next_token();
self.expect_keyword("JOIN")?;
Join {
relation: self.parse_table_factor()?,
join_operator: JoinOperator::Cross,
}
}
_ => {
let natural = self.parse_keyword("NATURAL");
let peek_keyword = if let Some(Token::SQLWord(kw)) = self.peek_token() {
kw.keyword
} else {
String::default()
};

let join_operator_type = match peek_keyword.as_ref() {
"INNER" | "JOIN" => {
let _ = self.parse_keyword("INNER");
self.expect_keyword("JOIN")?;
JoinOperator::Inner
}
kw @ "LEFT" | kw @ "RIGHT" | kw @ "FULL" => {
let _ = self.next_token();
let _ = self.parse_keyword("OUTER");
self.expect_keyword("JOIN")?;
match kw {
"LEFT" => JoinOperator::LeftOuter,
"RIGHT" => JoinOperator::RightOuter,
"FULL" => JoinOperator::FullOuter,
_ => unreachable!(),
}
}
_ if natural => {
return self.expected("a join type after NATURAL", self.peek_token());
}
_ => break,
};
let relation = self.parse_table_factor()?;
let join_constraint = self.parse_join_constraint(natural)?;
Join {
relation,
join_operator: join_operator_type(join_constraint),
}
}
};
joins.push(join);
}
Ok(TableWithJoins { relation, joins })
}

/// A table name or a parenthesized subquery, followed by optional `[AS] alias`
pub fn parse_table_factor(&mut self) -> Result<TableFactor, ParserError> {
let lateral = self.parse_keyword("LATERAL");
Expand All @@ -1627,10 +1688,9 @@ impl Parser {
} else if lateral {
parser_err!("Expected subquery after LATERAL, found nested join".to_string())
} else {
let base = Box::new(self.parse_table_factor()?);
let joins = self.parse_joins()?;
let table_reference = self.parse_table_and_joins()?;
self.expect_token(&Token::RParen)?;
Ok(TableFactor::NestedJoin { base, joins })
Ok(TableFactor::NestedJoin(Box::new(table_reference)))
}
} else if lateral {
self.expected("subquery after LATERAL", self.peek_token())
Expand Down Expand Up @@ -1677,68 +1737,6 @@ impl Parser {
}
}

fn parse_joins(&mut self) -> Result<Vec<Join>, ParserError> {
let mut joins = vec![];
loop {
let join = match &self.peek_token() {
Some(Token::Comma) => {
self.next_token();
Join {
relation: self.parse_table_factor()?,
join_operator: JoinOperator::Implicit,
}
}
Some(Token::SQLWord(kw)) if kw.keyword == "CROSS" => {
self.next_token();
self.expect_keyword("JOIN")?;
Join {
relation: self.parse_table_factor()?,
join_operator: JoinOperator::Cross,
}
}
_ => {
let natural = self.parse_keyword("NATURAL");
let peek_keyword = if let Some(Token::SQLWord(kw)) = self.peek_token() {
kw.keyword
} else {
String::default()
};

let join_operator_type = match peek_keyword.as_ref() {
"INNER" | "JOIN" => {
let _ = self.parse_keyword("INNER");
self.expect_keyword("JOIN")?;
JoinOperator::Inner
}
kw @ "LEFT" | kw @ "RIGHT" | kw @ "FULL" => {
let _ = self.next_token();
let _ = self.parse_keyword("OUTER");
self.expect_keyword("JOIN")?;
match kw {
"LEFT" => JoinOperator::LeftOuter,
"RIGHT" => JoinOperator::RightOuter,
"FULL" => JoinOperator::FullOuter,
_ => unreachable!(),
}
}
_ if natural => {
return self.expected("a join type after NATURAL", self.peek_token());
}
_ => break,
};
let relation = self.parse_table_factor()?;
let join_constraint = self.parse_join_constraint(natural)?;
Join {
relation,
join_operator: join_operator_type(join_constraint),
}
}
};
joins.push(join);
}
Ok(joins)
}

/// Parse an INSERT statement
pub fn parse_insert(&mut self) -> Result<SQLStatement, ParserError> {
self.expect_keyword("INTO")?;
Expand Down
10 changes: 7 additions & 3 deletions src/test_utils.rs
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Expand Up @@ -109,9 +109,13 @@ pub fn all_dialects() -> TestedDialects {
}
}

pub fn only<T>(v: &[T]) -> &T {
assert_eq!(1, v.len());
v.first().unwrap()
pub fn only<T>(v: impl IntoIterator<Item = T>) -> T {
let mut iter = v.into_iter();
if let (Some(item), None) = (iter.next(), iter.next()) {
item
} else {
panic!("only called on collection without exactly one item")
}
}

pub fn expr_from_projection(item: &SQLSelectItem) -> &ASTNode {
Expand Down
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