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Support CASE operand WHEN expected_value THEN ..

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Another part of #15
This commit is contained in:
Nickolay Ponomarev 2019-04-27 20:09:53 +03:00
parent 2aa4c267e7
commit e5e3d71354
3 changed files with 62 additions and 37 deletions
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52
src/sqlparser.rs
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@ -336,33 +336,33 @@ impl Parser {
}
pub fn parse_case_expression(&mut self) -> Result<ASTNode, ParserError> {
if self.parse_keyword("WHEN") {
let mut conditions = vec![];
let mut results = vec![];
loop {
conditions.push(self.parse_expr()?);
self.expect_keyword("THEN")?;
results.push(self.parse_expr()?);
if !self.parse_keyword("WHEN") {
break;
}
}
let else_result = if self.parse_keyword("ELSE") {
Some(Box::new(self.parse_expr()?))
} else {
None
};
self.expect_keyword("END")?;
Ok(ASTNode::SQLCase {
conditions,
results,
else_result,
})
} else {
// TODO: implement "simple" case
// https://jakewheat.github.io/sql-overview/sql-2011-foundation-grammar.html#simple-case
parser_err!("Simple case not implemented")
let mut operand = None;
if !self.parse_keyword("WHEN") {
operand = Some(Box::new(self.parse_expr()?));
self.expect_keyword("WHEN")?;
}
let mut conditions = vec![];
let mut results = vec![];
loop {
conditions.push(self.parse_expr()?);
self.expect_keyword("THEN")?;
results.push(self.parse_expr()?);
if !self.parse_keyword("WHEN") {
break;
}
}
let else_result = if self.parse_keyword("ELSE") {
Some(Box::new(self.parse_expr()?))
} else {
None
};
self.expect_keyword("END")?;
Ok(ASTNode::SQLCase {
operand,
conditions,
results,
else_result,
})
}
/// Parse a SQL CAST function e.g. `CAST(expr AS FLOAT)`