MySQL: Add support for casting using the BINARY keyword (apache#2146)

Author: yoavcloud

src/dialect/mod.rs

@@ -1242,6 +1242,12 @@ pub trait Dialect: Debug + Any {
     fn supports_double_ampersand_operator(&self) -> bool {
         false
     }
+
+    /// Returns true if the dialect supports casting an expression to a binary type
+    /// using the `BINARY <expr>` syntax.
+    fn supports_binary_kw_as_cast(&self) -> bool {
+        false
+    }
 }
 
 /// Operators for which precedence must be defined.

src/dialect/mysql.rs

@@ -176,6 +176,12 @@ impl Dialect for MySqlDialect {
     fn supports_double_ampersand_operator(&self) -> bool {
         true
     }
+
+    /// Deprecated functionality by MySQL but still supported
+    /// See: <https://dev.mysql.com/doc/refman/8.4/en/cast-functions.html#operator_binary>
+    fn supports_binary_kw_as_cast(&self) -> bool {
+        true
+    }
 }
 
 /// `LOCK TABLES`

src/parser/mod.rs

@@ -1645,6 +1645,15 @@ impl<'a> Parser<'a> {
                 // an unary negation `NOT ('a' LIKE 'b')`. To solve this, we don't accept the
                 // `type 'string'` syntax for the custom data types at all.
                 DataType::Custom(..) => parser_err!("dummy", loc),
+                // MySQL supports using the `BINARY` keyword as a cast to binary type.
+                DataType::Binary(..) if self.dialect.supports_binary_kw_as_cast() => {
+                    Ok(Expr::Cast {
+                        kind: CastKind::Cast,
+                        expr: Box::new(parser.parse_expr()?),
+                        data_type: DataType::Binary(None),
+                        format: None,
+                    })
+                }
                 data_type => Ok(Expr::TypedString(TypedString {
                     data_type,
                     value: parser.parse_value()?,

tests/sqlparser_common.rs

@@ -18087,3 +18087,9 @@ fn test_parse_key_value_options_trailing_semicolon() {
         "CREATE USER u1 option1='value1' option2='value2'",
     );
 }
+
+#[test]
+fn test_binary_kw_as_cast() {
+    all_dialects_where(|d| d.supports_binary_kw_as_cast())
+        .one_statement_parses_to("SELECT BINARY 1+1", "SELECT CAST(1 + 1 AS BINARY)");
+}