feat: Support SET NAMES literal [COLLATE literal] (apache#558)

* feat: Support SET NAMES literal [COLLATE literal]

* feat: Support SET NAMES DEFAULT

* clippy

Author: ovr

src/ast/mod.rs

@@ -992,6 +992,17 @@ pub enum Statement {
         variable: ObjectName,
         value: Vec<SetVariableValue>,
     },
+    /// SET NAMES 'charset_name' [COLLATE 'collation_name']
+    ///
+    /// Note: this is a MySQL-specific statement.
+    SetNames {
+        charset_name: String,
+        collation_name: Option<String>,
+    },
+    /// SET NAMES DEFAULT
+    ///
+    /// Note: this is a MySQL-specific statement.
+    SetNamesDefault {},
     /// SHOW <variable>
     ///
     /// Note: this is a PostgreSQL-specific statement.
@@ -1788,6 +1799,25 @@ impl fmt::Display for Statement {
                     value = display_comma_separated(value)
                 )
             }
+            Statement::SetNames {
+                charset_name,
+                collation_name,
+            } => {
+                f.write_str("SET NAMES ")?;
+                f.write_str(charset_name)?;
+
+                if let Some(collation) = collation_name {
+                    f.write_str(" COLLATE ")?;
+                    f.write_str(collation)?;
+                };
+
+                Ok(())
+            }
+            Statement::SetNamesDefault {} => {
+                f.write_str("SET NAMES DEFAULT")?;
+
+                Ok(())
+            }
             Statement::ShowVariable { variable } => {
                 write!(f, "SHOW")?;
                 if !variable.is_empty() {

src/parser.rs

@@ -3652,7 +3652,25 @@ impl<'a> Parser<'a> {
         }
 
         let variable = self.parse_object_name()?;
-        if self.consume_token(&Token::Eq) || self.parse_keyword(Keyword::TO) {
+        if variable.to_string().eq_ignore_ascii_case("NAMES")
+            && dialect_of!(self is MySqlDialect | GenericDialect)
+        {
+            if self.parse_keyword(Keyword::DEFAULT) {
+                return Ok(Statement::SetNamesDefault {});
+            }
+
+            let charset_name = self.parse_literal_string()?;
+            let collation_name = if self.parse_one_of_keywords(&[Keyword::COLLATE]).is_some() {
+                Some(self.parse_literal_string()?)
+            } else {
+                None
+            };
+
+            Ok(Statement::SetNames {
+                charset_name,
+                collation_name,
+            })
+        } else if self.consume_token(&Token::Eq) || self.parse_keyword(Keyword::TO) {
             let mut values = vec![];
             loop {
                 let token = self.peek_token();

tests/sqlparser_mysql.rs

@@ -890,6 +890,41 @@ fn parse_table_colum_option_on_update() {
     }
 }
 
+#[test]
+fn parse_set_names() {
+    let stmt = mysql_and_generic().verified_stmt("SET NAMES utf8mb4");
+    assert_eq!(
+        stmt,
+        Statement::SetNames {
+            charset_name: "utf8mb4".to_string(),
+            collation_name: None,
+        }
+    );
+
+    let stmt = mysql_and_generic().verified_stmt("SET NAMES utf8mb4 COLLATE bogus");
+    assert_eq!(
+        stmt,
+        Statement::SetNames {
+            charset_name: "utf8mb4".to_string(),
+            collation_name: Some("bogus".to_string()),
+        }
+    );
+
+    let stmt = mysql_and_generic()
+        .parse_sql_statements("set names utf8mb4 collate bogus")
+        .unwrap();
+    assert_eq!(
+        stmt,
+        vec![Statement::SetNames {
+            charset_name: "utf8mb4".to_string(),
+            collation_name: Some("bogus".to_string()),
+        }]
+    );
+
+    let stmt = mysql_and_generic().verified_stmt("SET NAMES DEFAULT");
+    assert_eq!(stmt, Statement::SetNamesDefault {});
+}
+
 fn mysql() -> TestedDialects {
     TestedDialects {
         dialects: vec![Box::new(MySqlDialect {})],