Add support for INSERT INTO VALUE (#2085)

src/ast/query.rs

@@ -3135,12 +3135,18 @@ pub struct Values {
     /// Was there an explicit ROWs keyword (MySQL)?
     /// <https://dev.mysql.com/doc/refman/8.0/en/values.html>
     pub explicit_row: bool,
+    // MySql supports both VALUES and VALUE keywords.
+    // <https://dev.mysql.com/doc/refman/9.2/en/insert.html>
+    pub value_keyword: bool,
     pub rows: Vec<Vec<Expr>>,
 }
 
 impl fmt::Display for Values {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.write_str("VALUES")?;
+        match self.value_keyword {
+            true => f.write_str("VALUE")?,
+            false => f.write_str("VALUES")?,
+        };
         let prefix = if self.explicit_row { "ROW" } else { "" };
         let mut delim = "";
         for row in &self.rows {

src/ast/spans.rs

@@ -223,6 +223,7 @@ impl Spanned for Values {
     fn span(&self) -> Span {
         let Values {
             explicit_row: _, // bool,
+            value_keyword: _,
             rows,
         } = self;
 

src/parser/mod.rs

@@ -12533,7 +12533,10 @@ impl<'a> Parser<'a> {
             SetExpr::Query(subquery)
         } else if self.parse_keyword(Keyword::VALUES) {
             let is_mysql = dialect_of!(self is MySqlDialect);
-            SetExpr::Values(self.parse_values(is_mysql)?)
+            SetExpr::Values(self.parse_values(is_mysql, false)?)
+        } else if self.parse_keyword(Keyword::VALUE) {
+            let is_mysql = dialect_of!(self is MySqlDialect);
+            SetExpr::Values(self.parse_values(is_mysql, true)?)
         } else if self.parse_keyword(Keyword::TABLE) {
             SetExpr::Table(Box::new(self.parse_as_table()?))
         } else {
@@ -13837,7 +13840,7 @@ impl<'a> Parser<'a> {
             // Snowflake and Databricks allow syntax like below:
             // SELECT * FROM VALUES (1, 'a'), (2, 'b') AS t (col1, col2)
             // where there are no parentheses around the VALUES clause.
-            let values = SetExpr::Values(self.parse_values(false)?);
+            let values = SetExpr::Values(self.parse_values(false, false)?);
             let alias = self.maybe_parse_table_alias()?;
             Ok(TableFactor::Derived {
                 lateral: false,
@@ -16504,7 +16507,11 @@ impl<'a> Parser<'a> {
         })
     }
 
-    pub fn parse_values(&mut self, allow_empty: bool) -> Result<Values, ParserError> {
+    pub fn parse_values(
+        &mut self,
+        allow_empty: bool,
+        value_keyword: bool,
+    ) -> Result<Values, ParserError> {
         let mut explicit_row = false;
 
         let rows = self.parse_comma_separated(|parser| {
@@ -16522,7 +16529,11 @@ impl<'a> Parser<'a> {
                 Ok(exprs)
             }
         })?;
-        Ok(Values { explicit_row, rows })
+        Ok(Values {
+            explicit_row,
+            rows,
+            value_keyword,
+        })
     }
 
     pub fn parse_start_transaction(&mut self) -> Result<Statement, ParserError> {
@@ -16937,7 +16948,7 @@ impl<'a> Parser<'a> {
                         MergeInsertKind::Row
                     } else {
                         self.expect_keyword_is(Keyword::VALUES)?;
-                        let values = self.parse_values(is_mysql)?;
+                        let values = self.parse_values(is_mysql, false)?;
                         MergeInsertKind::Values(values)
                     };
                     MergeAction::Insert(MergeInsertExpr { columns, kind })