provide ILIKE support

cherry-picked from a9e6f77.

This introduces support for ILIKE and NOT ILIKE. ILIKE is the
case-insensitive variant of LIKE. Systems such as Postgres, Redshift,
and Snowflake provide this variant.[1][2][3]

[1] https://www.postgresql.org/docs/7.3/functions-matching.html
[2] https://docs.aws.amazon.com/redshift/latest/dg/r_patternmatching_condition_like.html
[3] https://docs.snowflake.com/en/sql-reference/functions/ilike.html

Author: maxcountryman

src/ast/mod.rs

@@ -1585,6 +1585,7 @@ impl fmt::Display for TransactionIsolationLevel {
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum ShowStatementFilter {
     Like(String),
+    ILike(String),
     Where(Expr),
 }
 
@@ -1593,6 +1594,7 @@ impl fmt::Display for ShowStatementFilter {
         use ShowStatementFilter::*;
         match self {
             Like(pattern) => write!(f, "LIKE '{}'", value::escape_single_quote_string(pattern)),
+            ILike(pattern) => write!(f, "ILIKE {}", value::escape_single_quote_string(pattern)),
             Where(expr) => write!(f, "WHERE {}", expr),
         }
     }

src/ast/operator.rs

@@ -72,6 +72,8 @@ pub enum BinaryOperator {
     Or,
     Like,
     NotLike,
+    ILike,
+    NotILike,
     BitwiseOr,
     BitwiseAnd,
     BitwiseXor,
@@ -100,6 +102,8 @@ impl fmt::Display for BinaryOperator {
             BinaryOperator::Or => "OR",
             BinaryOperator::Like => "LIKE",
             BinaryOperator::NotLike => "NOT LIKE",
+            BinaryOperator::ILike => "ILIKE",
+            BinaryOperator::NotILike => "NOT ILIKE",
             BinaryOperator::BitwiseOr => "|",
             BinaryOperator::BitwiseAnd => "&",
             BinaryOperator::BitwiseXor => "^",

src/dialect/keywords.rs

@@ -237,6 +237,7 @@ define_keywords!(
     IDENTITY,
     IF,
     IGNORE,
+    ILIKE,
     IN,
     INDEX,
     INDICATOR,

src/parser.rs

@@ -875,9 +875,12 @@ impl<'a> Parser<'a> {
                 Keyword::AND => Some(BinaryOperator::And),
                 Keyword::OR => Some(BinaryOperator::Or),
                 Keyword::LIKE => Some(BinaryOperator::Like),
+                Keyword::ILIKE => Some(BinaryOperator::ILike),
                 Keyword::NOT => {
                     if self.parse_keyword(Keyword::LIKE) {
                         Some(BinaryOperator::NotLike)
+                    } else if self.parse_keyword(Keyword::ILIKE) {
+                        Some(BinaryOperator::NotILike)
                     } else {
                         None
                     }
@@ -1011,12 +1014,14 @@ impl<'a> Parser<'a> {
                 Token::Word(w) if w.keyword == Keyword::IN => Ok(Self::BETWEEN_PREC),
                 Token::Word(w) if w.keyword == Keyword::BETWEEN => Ok(Self::BETWEEN_PREC),
                 Token::Word(w) if w.keyword == Keyword::LIKE => Ok(Self::BETWEEN_PREC),
+                Token::Word(w) if w.keyword == Keyword::ILIKE => Ok(Self::BETWEEN_PREC),
                 _ => Ok(0),
             },
             Token::Word(w) if w.keyword == Keyword::IS => Ok(17),
             Token::Word(w) if w.keyword == Keyword::IN => Ok(Self::BETWEEN_PREC),
             Token::Word(w) if w.keyword == Keyword::BETWEEN => Ok(Self::BETWEEN_PREC),
             Token::Word(w) if w.keyword == Keyword::LIKE => Ok(Self::BETWEEN_PREC),
+            Token::Word(w) if w.keyword == Keyword::ILIKE => Ok(Self::BETWEEN_PREC),
             Token::Eq
             | Token::Lt
             | Token::LtEq
@@ -1517,7 +1522,7 @@ impl<'a> Parser<'a> {
     ) -> Result<Statement, ParserError> {
         let if_not_exists = self.parse_keywords(&[Keyword::IF, Keyword::NOT, Keyword::EXISTS]);
         let table_name = self.parse_object_name()?;
-        let like = if self.parse_keyword(Keyword::LIKE) {
+        let like = if self.parse_keyword(Keyword::LIKE) || self.parse_keyword(Keyword::ILIKE) {
             self.parse_object_name().ok()
         } else {
             None
@@ -2592,6 +2597,10 @@ impl<'a> Parser<'a> {
             Ok(Some(ShowStatementFilter::Like(
                 self.parse_literal_string()?,
             )))
+        } else if self.parse_keyword(Keyword::ILIKE) {
+            Ok(Some(ShowStatementFilter::ILike(
+                self.parse_literal_string()?,
+            )))
         } else if self.parse_keyword(Keyword::WHERE) {
             Ok(Some(ShowStatementFilter::Where(self.parse_expr()?)))
         } else {

tests/sqlparser_common.rs

@@ -687,6 +687,51 @@ fn parse_like() {
     chk(true);
 }
 
+#[test]
+fn parse_ilike() {
+    fn chk(negated: bool) {
+        let sql = &format!(
+            "SELECT * FROM customers WHERE name {}ILIKE '%a'",
+            if negated { "NOT " } else { "" }
+        );
+        let select = verified_only_select(sql);
+        assert_eq!(
+            Expr::BinaryOp {
+                left: Box::new(Expr::Identifier(Ident::new("name"))),
+                op: if negated {
+                    BinaryOperator::NotILike
+                } else {
+                    BinaryOperator::ILike
+                },
+                right: Box::new(Expr::Value(Value::SingleQuotedString("%a".to_string()))),
+            },
+            select.selection.unwrap()
+        );
+
+        // This statement tests that LIKE and NOT LIKE have the same precedence.
+        // This was previously mishandled (#81).
+        let sql = &format!(
+            "SELECT * FROM customers WHERE name {}ILIKE '%a' IS NULL",
+            if negated { "NOT " } else { "" }
+        );
+        let select = verified_only_select(sql);
+        assert_eq!(
+            Expr::IsNull(Box::new(Expr::BinaryOp {
+                left: Box::new(Expr::Identifier(Ident::new("name"))),
+                op: if negated {
+                    BinaryOperator::NotILike
+                } else {
+                    BinaryOperator::ILike
+                },
+                right: Box::new(Expr::Value(Value::SingleQuotedString("%a".to_string()))),
+            })),
+            select.selection.unwrap()
+        );
+    }
+    chk(false);
+    chk(true);
+}
+
 #[test]
 fn parse_in_list() {
     fn chk(negated: bool) {