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Merged
merged 3 commits into from
Jun 3, 2019
Merged

Refactor parse_joins #87

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8206523
Minor consume_token()-related simplifications
nickolay Jun 2, 2019
665b9df
Refactor parse_joins, pt.1: INNER/OUTER joins
nickolay Jun 2, 2019
d0f2de0
Refactor parse_joins, pt.2: implicit/cross/natural joins
nickolay Jun 2, 2019
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12 changes: 6 additions & 6 deletions src/sqlast/query.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -271,34 +271,34 @@ impl ToString for Join {
}
fn suffix(constraint: &JoinConstraint) -> String {
match constraint {
JoinConstraint::On(expr) => format!("ON {}", expr.to_string()),
JoinConstraint::Using(attrs) => format!("USING({})", attrs.join(", ")),
JoinConstraint::On(expr) => format!(" ON {}", expr.to_string()),
JoinConstraint::Using(attrs) => format!(" USING({})", attrs.join(", ")),
_ => "".to_string(),
}
}
match &self.join_operator {
JoinOperator::Inner(constraint) => format!(
" {}JOIN {} {}",
" {}JOIN {}{}",
prefix(constraint),
self.relation.to_string(),
suffix(constraint)
),
JoinOperator::Cross => format!(" CROSS JOIN {}", self.relation.to_string()),
JoinOperator::Implicit => format!(", {}", self.relation.to_string()),
JoinOperator::LeftOuter(constraint) => format!(
" {}LEFT JOIN {} {}",
" {}LEFT JOIN {}{}",
prefix(constraint),
self.relation.to_string(),
suffix(constraint)
),
JoinOperator::RightOuter(constraint) => format!(
" {}RIGHT JOIN {} {}",
" {}RIGHT JOIN {}{}",
prefix(constraint),
self.relation.to_string(),
suffix(constraint)
),
JoinOperator::FullOuter(constraint) => format!(
" {}FULL JOIN {} {}",
" {}FULL JOIN {}{}",
prefix(constraint),
self.relation.to_string(),
suffix(constraint)
Expand Down
135 changes: 49 additions & 86 deletions src/sqlparser.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -702,14 +702,10 @@ impl Parser {
/// Consume the next token if it matches the expected token, otherwise return false
#[must_use]
pub fn consume_token(&mut self, expected: &Token) -> bool {
match self.peek_token() {
Some(ref t) => {
if *t == *expected {
self.next_token();
true
} else {
false
}
match &self.peek_token() {
Some(t) if *t == *expected => {
self.next_token();
true
}
_ => false,
}
Expand Down Expand Up @@ -1503,90 +1499,62 @@ impl Parser {
fn parse_joins(&mut self) -> Result<Vec<Join>, ParserError> {
let mut joins = vec![];
loop {
let natural = match &self.peek_token() {
Some(Token::Comma) => {
self.next_token();
let relation = self.parse_table_factor()?;
let join = Join {
relation,
join_operator: JoinOperator::Implicit,
};
joins.push(join);
continue;
}
Some(Token::SQLWord(kw)) if kw.keyword == "CROSS" => {
self.next_token();
self.expect_keyword("JOIN")?;
let relation = self.parse_table_factor()?;
let join = Join {
relation,
join_operator: JoinOperator::Cross,
};
joins.push(join);
continue;
}
Some(Token::SQLWord(kw)) if kw.keyword == "NATURAL" => {
self.next_token();
true
}
Some(_) => false,
None => return Ok(joins),
};

let join = match &self.peek_token() {
Some(Token::SQLWord(kw)) if kw.keyword == "INNER" => {
self.next_token();
self.expect_keyword("JOIN")?;
Join {
relation: self.parse_table_factor()?,
join_operator: JoinOperator::Inner(self.parse_join_constraint(natural)?),
}
}
Some(Token::SQLWord(kw)) if kw.keyword == "JOIN" => {
self.next_token();
Join {
relation: self.parse_table_factor()?,
join_operator: JoinOperator::Inner(self.parse_join_constraint(natural)?),
}
}
Some(Token::SQLWord(kw)) if kw.keyword == "LEFT" => {
Some(Token::Comma) => {
self.next_token();
let _ = self.parse_keyword("OUTER");
self.expect_keyword("JOIN")?;
Join {
relation: self.parse_table_factor()?,
join_operator: JoinOperator::LeftOuter(
self.parse_join_constraint(natural)?,
),
join_operator: JoinOperator::Implicit,
}
}
Some(Token::SQLWord(kw)) if kw.keyword == "RIGHT" => {
Some(Token::SQLWord(kw)) if kw.keyword == "CROSS" => {
self.next_token();
let _ = self.parse_keyword("OUTER");
self.expect_keyword("JOIN")?;
Join {
relation: self.parse_table_factor()?,
join_operator: JoinOperator::RightOuter(
self.parse_join_constraint(natural)?,
),
join_operator: JoinOperator::Cross,
}
}
Some(Token::SQLWord(kw)) if kw.keyword == "FULL" => {
self.next_token();
let _ = self.parse_keyword("OUTER");
self.expect_keyword("JOIN")?;
_ => {
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: self.parse_table_factor()?,
join_operator: JoinOperator::FullOuter(
self.parse_join_constraint(natural)?,
),
relation,
join_operator: join_operator_type(join_constraint),
}
}
_ => break,
};
joins.push(join);
}

Ok(joins)
}

Expand All @@ -1611,10 +1579,9 @@ impl Parser {
let mut expr_list: Vec<ASTNode> = vec![];
loop {
expr_list.push(self.parse_expr()?);
match self.peek_token() {
Some(Token::Comma) => self.next_token(),
_ => break,
};
if !self.consume_token(&Token::Comma) {
break;
}
}
Ok(expr_list)
}
Expand Down Expand Up @@ -1649,10 +1616,9 @@ impl Parser {
}
}

match self.peek_token() {
Some(Token::Comma) => self.next_token(),
_ => break,
};
if !self.consume_token(&Token::Comma) {
break;
}
}
Ok(projections)
}
Expand All @@ -1672,10 +1638,7 @@ impl Parser {
};

expr_list.push(SQLOrderByExpr { expr, asc });

if let Some(Token::Comma) = self.peek_token() {
self.next_token();
} else {
if !self.consume_token(&Token::Comma) {
break;
}
}
Expand Down
37 changes: 37 additions & 0 deletions tests/sqlparser_common.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1218,6 +1218,43 @@ fn parse_joins_using() {
);
}

#[test]
fn parse_natural_join() {
fn natural_join(f: impl Fn(JoinConstraint) -> JoinOperator) -> Join {
Join {
relation: TableFactor::Table {
name: SQLObjectName(vec!["t2".to_string()]),
alias: None,
args: vec![],
with_hints: vec![],
},
join_operator: f(JoinConstraint::Natural),
}
}
assert_eq!(
verified_only_select("SELECT * FROM t1 NATURAL JOIN t2").joins,
vec![natural_join(JoinOperator::Inner)]
);
assert_eq!(
verified_only_select("SELECT * FROM t1 NATURAL LEFT JOIN t2").joins,
vec![natural_join(JoinOperator::LeftOuter)]
);
assert_eq!(
verified_only_select("SELECT * FROM t1 NATURAL RIGHT JOIN t2").joins,
vec![natural_join(JoinOperator::RightOuter)]
);
assert_eq!(
verified_only_select("SELECT * FROM t1 NATURAL FULL JOIN t2").joins,
vec![natural_join(JoinOperator::FullOuter)]
);

let sql = "SELECT * FROM t1 natural";
assert_eq!(
ParserError::ParserError("Expected a join type after NATURAL, found: EOF".to_string()),
parse_sql_statements(sql).unwrap_err(),
);
}

#[test]
fn parse_complex_join() {
let sql = "SELECT c1, c2 FROM t1, t4 JOIN t2 ON t2.c = t1.c LEFT JOIN t3 USING(q, c) WHERE t4.c = t1.c";
Expand Down