feat: support drop view in sqlite

Author: taozhi8833998

pegjs/mariadb.pegjs

@@ -891,7 +891,7 @@ drop_stmt
           keyword: r.toLowerCase(),
           prefix: ife,
           name: t,
-          options: [{ type: 'origin', value: op }],
+          options: op && [{ type: 'origin', value: op }],
         }
       };
     }

pegjs/mysql.pegjs

@@ -1092,7 +1092,7 @@ drop_stmt
           keyword: r.toLowerCase(),
           prefix: ife,
           name: t,
-          options: [{ type: 'origin', value: op }],
+          options: op && [{ type: 'origin', value: op }],
         }
       };
     }

pegjs/sqlite.pegjs

@@ -289,6 +289,11 @@ if_not_exists_stmt
     return 'IF NOT EXISTS'
   }
 
+if_exists
+  = 'if'i __ 'exists'i {
+    return 'if exists'
+  }
+
 create_trigger_stmt
   = kw: KW_CREATE __
   tp:(KW_TEMPORARY / KW_TEMP)? __
@@ -622,6 +627,21 @@ drop_stmt
         }
       };
     }
+  / a:KW_DROP __
+    r:KW_VIEW __
+    ife:if_exists? __
+    t:table_ref_list {
+      return {
+        tableList: Array.from(tableList),
+        columnList: columnListTableAlias(columnList),
+        ast: {
+          type: a.toLowerCase(),
+          keyword: r.toLowerCase(),
+          prefix: ife,
+          name: t,
+        }
+      };
+    }
   / a:KW_DROP __
     r:KW_INDEX __
     i:column_ref __

test/sqlite.spec.js

@@ -155,10 +155,12 @@ describe('sqlite', () => {
     expect(parser.sqlify(ast, DEFAULT_OPT)).to.be.equal('CREATE TABLE `Test` (`id` INT(11) NOT NULL, `name` VARCHAR(255) NOT NULL, PRIMARY KEY (`id`), UNIQUE (`name`))')
   })
 
-  it('should support create view', () => {
+  it('should support create or drop view', () => {
     let sql = 'create view v1 as select * from t1'
     expect(getParsedSql(sql)).to.be.equal('CREATE VIEW `v1` AS SELECT * FROM `t1`')
     sql = 'create temp view if not exists s.v1(a, b, c) as select * from t1'
     expect(getParsedSql(sql)).to.be.equal('CREATE TEMP VIEW IF NOT EXISTS `s`.`v1` (`a`, `b`, `c`) AS SELECT * FROM `t1`')
+    sql = 'DROP VIEW IF EXISTS view_name;',
+    expect(getParsedSql(sql)).to.be.equal('DROP VIEW IF EXISTS `view_name`')
   })
 })