Support NUMERIC without precision or scale

https://jakewheat.github.io/sql-overview/sql-2011-foundation-grammar.html#exact-numeric-type

Author: nickolay

src/sqlast/sqltype.rs

@@ -17,8 +17,8 @@ pub enum SQLType {
     Varbinary(usize),
     /// Large binary object e.g. BLOB(1000)
     Blob(usize),
-    /// Decimal type with precision and optional scale e.g. DECIMAL(10,2)
-    Decimal(usize, Option<usize>),
+    /// Decimal type with optional precision and scale e.g. DECIMAL(10,2)
+    Decimal(Option<usize>, Option<usize>),
     /// Small integer
     SmallInt,
     /// Integer
@@ -75,9 +75,13 @@ impl ToString for SQLType {
             SQLType::Blob(size) => format!("blob({})", size),
             SQLType::Decimal(precision, scale) => {
                 if let Some(scale) = scale {
-                    format!("numeric({},{})", precision, scale)
+                    format!("numeric({},{})", precision.unwrap(), scale)
                 } else {
-                    format!("numeric({})", precision)
+                    if let Some(precision) = precision {
+                        format!("numeric({})", precision)
+                    } else {
+                        format!("numeric")
+                    }
                 }
             }
             SQLType::SmallInt => "smallint".to_string(),

src/sqlparser.rs

@@ -1166,7 +1166,7 @@ impl Parser {
 
     pub fn parse_optional_precision_scale(
         &mut self,
-    ) -> Result<(usize, Option<usize>), ParserError> {
+    ) -> Result<(Option<usize>, Option<usize>), ParserError> {
         if self.consume_token(&Token::LParen) {
             let n = self.parse_literal_int()?;
             let scale = if self.consume_token(&Token::Comma) {
@@ -1175,9 +1175,9 @@ impl Parser {
                 None
             };
             self.expect_token(&Token::RParen)?;
-            Ok((n as usize, scale))
+            Ok((Some(n as usize), scale))
         } else {
-            parser_err!("Expecting `(`")
+            Ok((None, None))
         }
     }