Support drop sequence statement (#673)

* Add ObjectType Sequence

* Drop sequence test cases added.

* Parser and Drop statement Display updated.

* Parser and Drop statement Display updated.

* Fix compile errors

* add new test case

Author: samjay000

src/ast/mod.rs

@@ -1184,6 +1184,9 @@ pub enum Statement {
         /// Whether `CASCADE` was specified. This will be `false` when
         /// `RESTRICT` or no drop behavior at all was specified.
         cascade: bool,
+        /// Whether `RESTRICT` was specified. This will be `false` when
+        /// `CASCADE` or no drop behavior at all was specified.
+        restrict: bool,
         /// Hive allows you specify whether the table's stored data will be
         /// deleted along with the dropped table
         purge: bool,
@@ -2143,14 +2146,16 @@ impl fmt::Display for Statement {
                 if_exists,
                 names,
                 cascade,
+                restrict,
                 purge,
             } => write!(
                 f,
-                "DROP {}{} {}{}{}",
+                "DROP {}{} {}{}{}{}",
                 object_type,
                 if *if_exists { " IF EXISTS" } else { "" },
                 display_comma_separated(names),
                 if *cascade { " CASCADE" } else { "" },
+                if *restrict { " RESTRICT" } else { "" },
                 if *purge { " PURGE" } else { "" }
             ),
             Statement::Discard { object_type } => {
@@ -2910,6 +2915,7 @@ pub enum ObjectType {
     Index,
     Schema,
     Role,
+    Sequence,
 }
 
 impl fmt::Display for ObjectType {
@@ -2920,6 +2926,7 @@ impl fmt::Display for ObjectType {
             ObjectType::Index => "INDEX",
             ObjectType::Schema => "SCHEMA",
             ObjectType::Role => "ROLE",
+            ObjectType::Sequence => "SEQUENCE",
         })
     }
 }

src/parser.rs

@@ -2441,9 +2441,11 @@ impl<'a> Parser<'a> {
             ObjectType::Role
         } else if self.parse_keyword(Keyword::SCHEMA) {
             ObjectType::Schema
+        } else if self.parse_keyword(Keyword::SEQUENCE) {
+            ObjectType::Sequence
         } else {
             return self.expected(
-                "TABLE, VIEW, INDEX, ROLE, or SCHEMA after DROP",
+                "TABLE, VIEW, INDEX, ROLE, SCHEMA, or SEQUENCE after DROP",
                 self.peek_token(),
             );
         };
@@ -2465,6 +2467,7 @@ impl<'a> Parser<'a> {
             if_exists,
             names,
             cascade,
+            restrict,
             purge,
         })
     }

tests/sqlparser_common.rs

@@ -4469,6 +4469,7 @@ fn parse_drop_table() {
             names,
             cascade,
             purge: _,
+            ..
         } => {
             assert!(!if_exists);
             assert_eq!(ObjectType::Table, object_type);
@@ -4489,6 +4490,7 @@ fn parse_drop_table() {
             names,
             cascade,
             purge: _,
+            ..
         } => {
             assert!(if_exists);
             assert_eq!(ObjectType::Table, object_type);

tests/sqlparser_postgres.rs

@@ -22,6 +22,25 @@ use sqlparser::ast::*;
 use sqlparser::dialect::{GenericDialect, PostgreSqlDialect};
 use sqlparser::parser::ParserError;
 
+#[test]
+fn parse_drop_sequence() {
+    // SimpleLogger::new().init().unwrap();
+    let sql1 = "DROP SEQUENCE IF EXISTS  name0 CASCADE";
+    pg().one_statement_parses_to(sql1, "DROP SEQUENCE IF EXISTS name0 CASCADE");
+    let sql2 = "DROP SEQUENCE IF EXISTS  name1 RESTRICT";
+    pg().one_statement_parses_to(sql2, "DROP SEQUENCE IF EXISTS name1 RESTRICT");
+    let sql3 = "DROP SEQUENCE  name2 CASCADE";
+    pg().one_statement_parses_to(sql3, "DROP SEQUENCE name2 CASCADE");
+    let sql4 = "DROP SEQUENCE  name2";
+    pg().one_statement_parses_to(sql4, "DROP SEQUENCE name2");
+    let sql5 = "DROP SEQUENCE  name0 CASCADE";
+    pg().one_statement_parses_to(sql5, "DROP SEQUENCE name0 CASCADE");
+    let sql6 = "DROP SEQUENCE  name1 RESTRICT";
+    pg().one_statement_parses_to(sql6, "DROP SEQUENCE name1 RESTRICT");
+    let sql7 = "DROP SEQUENCE  name1, name2, name3";
+    pg().one_statement_parses_to(sql7, "DROP SEQUENCE name1, name2, name3");
+}
+
 #[test]
 fn parse_create_table_with_defaults() {
     let sql = "CREATE TABLE public.customer (