rs: ignore/respect nulls

Author: donhcd

src/ast/mod.rs

@@ -207,6 +207,10 @@ pub enum Expr {
         expr: Box<Expr>,
         tz: String,
     },
+    IgnoreRespectNulls {
+        expr: Box<Expr>,
+        ignore: bool,
+    },
     /// CAST an expression to a different data type e.g. `CAST(foo AS VARCHAR(123))`
     Cast {
         /// try_cast is a snowflake feature
@@ -338,6 +342,13 @@ impl fmt::Display for Expr {
             }
             // rs/pg: https://docs.aws.amazon.com/redshift/latest/dg/r_AT_TIME_ZONE.html
             Expr::AtTimeZone { expr, tz } => write!(f, "{} AT TIME ZONE '{}'", expr, tz),
+            // rs: https://docs.aws.amazon.com/redshift/latest/dg/r_WF_first_value.html
+            Expr::IgnoreRespectNulls { expr, ignore } => write!(
+                f,
+                "{} {} NULLS",
+                expr,
+                if *ignore { "IGNORE" } else { "RESPECT " }
+            ),
             Expr::Cast {
                 try_cast,
                 expr,

src/dialect/keywords.rs

@@ -237,6 +237,7 @@ define_keywords!(
     HOUR,
     IDENTITY,
     IF,
+    IGNORE,
     ILIKE,
     IN,
     INDEX,
@@ -378,6 +379,7 @@ define_keywords!(
     RENAME,
     REPEATABLE,
     REPLACE,
+    RESPECT,
     RESTRICT,
     RESULT,
     RETURN,

src/parser.rs

@@ -827,6 +827,16 @@ impl<'a> Parser<'a> {
                         true,
                     ))
                 }
+                Keyword::IGNORE | Keyword::RESPECT => {
+                    self.expect_keyword(Keyword::NULLS)?;
+                    Ok((
+                        Expr::IgnoreRespectNulls {
+                            expr: Box::new(expr),
+                            ignore: w.value == "IGNORE",
+                        },
+                        true,
+                    ))
+                }
                 Keyword::IS => {
                     if self.parse_keyword(Keyword::NULL) {
                         Ok((Expr::IsNull(Box::new(expr)), true))
@@ -959,6 +969,9 @@ impl<'a> Parser<'a> {
         let token = self.peek_token();
         debug!("get_next_precedence() {:?}", token);
         match token {
+            Token::Word(w) if w.keyword == Keyword::IGNORE || w.keyword == Keyword::RESPECT => {
+                Ok(4)
+            }
             Token::Word(w) if w.keyword == Keyword::OR => Ok(5),
             Token::Word(w) if w.keyword == Keyword::AND => Ok(10),
             Token::Word(w) if w.keyword == Keyword::NOT => match self.peek_nth_token(1) {