feat: Support MySQL's DIV operator (apache#876)

* feat: MySQL's DIV operator

* fix: do not use `_` prefix for used variable

---------

Co-authored-by: Andrew Lamb <[email protected]>

Author: eitsupi

src/ast/operator.rs

@@ -85,6 +85,8 @@ pub enum BinaryOperator {
     BitwiseOr,
     BitwiseAnd,
     BitwiseXor,
+    /// MySQL [`DIV`](https://dev.mysql.com/doc/refman/8.0/en/arithmetic-functions.html) integer division
+    MyIntegerDivide,
     /// Support for custom operators (built by parsers outside this crate)
     Custom(String),
     PGBitwiseXor,
@@ -124,6 +126,7 @@ impl fmt::Display for BinaryOperator {
             BinaryOperator::BitwiseOr => f.write_str("|"),
             BinaryOperator::BitwiseAnd => f.write_str("&"),
             BinaryOperator::BitwiseXor => f.write_str("^"),
+            BinaryOperator::MyIntegerDivide => f.write_str("DIV"),
             BinaryOperator::Custom(s) => f.write_str(s),
             BinaryOperator::PGBitwiseXor => f.write_str("#"),
             BinaryOperator::PGBitwiseShiftLeft => f.write_str("<<"),

src/dialect/mysql.rs

@@ -10,7 +10,14 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::dialect::Dialect;
+#[cfg(not(feature = "std"))]
+use alloc::boxed::Box;
+
+use crate::{
+    ast::{BinaryOperator, Expr},
+    dialect::Dialect,
+    keywords::Keyword,
+};
 
 /// [MySQL](https://www.mysql.com/)
 #[derive(Debug)]
@@ -35,4 +42,22 @@ impl Dialect for MySqlDialect {
     fn is_delimited_identifier_start(&self, ch: char) -> bool {
         ch == '`'
     }
+
+    fn parse_infix(
+        &self,
+        parser: &mut crate::parser::Parser,
+        expr: &crate::ast::Expr,
+        _precedence: u8,
+    ) -> Option<Result<crate::ast::Expr, crate::parser::ParserError>> {
+        // Parse DIV as an operator
+        if parser.parse_keyword(Keyword::DIV) {
+            Some(Ok(Expr::BinaryOp {
+                left: Box::new(expr.clone()),
+                op: BinaryOperator::MyIntegerDivide,
+                right: Box::new(parser.parse_expr().unwrap()),
+            }))
+        } else {
+            None
+        }
+    }
 }

src/keywords.rs

@@ -211,6 +211,7 @@ define_keywords!(
     DISCONNECT,
     DISTINCT,
     DISTRIBUTE,
+    DIV,
     DO,
     DOUBLE,
     DOW,

src/parser.rs

@@ -1982,6 +1982,8 @@ impl<'a> Parser<'a> {
     const AND_PREC: u8 = 10;
     const OR_PREC: u8 = 5;
 
+    const DIV_OP_PREC: u8 = 40;
+
     /// Get the precedence of the next token
     pub fn get_next_precedence(&self) -> Result<u8, ParserError> {
         // allow the dialect to override precedence logic
@@ -2031,6 +2033,7 @@ impl<'a> Parser<'a> {
             Token::Word(w) if w.keyword == Keyword::ILIKE => Ok(Self::LIKE_PREC),
             Token::Word(w) if w.keyword == Keyword::SIMILAR => Ok(Self::LIKE_PREC),
             Token::Word(w) if w.keyword == Keyword::OPERATOR => Ok(Self::BETWEEN_PREC),
+            Token::Word(w) if w.keyword == Keyword::DIV => Ok(Self::DIV_OP_PREC),
             Token::Eq
             | Token::Lt
             | Token::LtEq

tests/sqlparser_mysql.rs

@@ -1407,3 +1407,8 @@ fn parse_string_introducers() {
     mysql().one_statement_parses_to("SELECT _utf8mb4'abc'", "SELECT _utf8mb4 'abc'");
     mysql().verified_stmt("SELECT _binary 'abc', _utf8mb4 'abc'");
 }
+
+#[test]
+fn parse_div_infix() {
+    mysql().verified_stmt(r#"SELECT 5 DIV 2"#);
+}