Allow to use the TABLE keyword in DESC|DESCRIBE|EXPLAIN TABLE statement (apache#1351)

Author: git-hulk

src/ast/mod.rs

@@ -2720,6 +2720,11 @@ pub enum Statement {
         describe_alias: DescribeAlias,
         /// Hive style `FORMATTED | EXTENDED`
         hive_format: Option<HiveDescribeFormat>,
+        /// Snowflake and ClickHouse support `DESC|DESCRIBE TABLE <table_name>` syntax
+        ///
+        /// [Snowflake](https://docs.snowflake.com/en/sql-reference/sql/desc-table.html)
+        /// [ClickHouse](https://clickhouse.com/docs/en/sql-reference/statements/describe-table)
+        has_table_keyword: bool,
         /// Table name
         #[cfg_attr(feature = "visitor", visit(with = "visit_relation"))]
         table_name: ObjectName,
@@ -2893,13 +2898,17 @@ impl fmt::Display for Statement {
             Statement::ExplainTable {
                 describe_alias,
                 hive_format,
+                has_table_keyword,
                 table_name,
             } => {
                 write!(f, "{describe_alias} ")?;
 
                 if let Some(format) = hive_format {
                     write!(f, "{} ", format)?;
                 }
+                if *has_table_keyword {
+                    write!(f, "TABLE ")?;
+                }
 
                 write!(f, "{table_name}")
             }

src/parser/mod.rs

@@ -7986,10 +7986,13 @@ impl<'a> Parser<'a> {
                     _ => {}
                 }
 
+                // only allow to use TABLE keyword for DESC|DESCRIBE statement
+                let has_table_keyword = self.parse_keyword(Keyword::TABLE);
                 let table_name = self.parse_object_name(false)?;
                 Ok(Statement::ExplainTable {
                     describe_alias,
                     hive_format,
+                    has_table_keyword,
                     table_name,
                 })
             }

tests/sqlparser_common.rs

@@ -4187,31 +4187,49 @@ fn run_explain_analyze(
 #[test]
 fn parse_explain_table() {
     let validate_explain =
-        |query: &str, expected_describe_alias: DescribeAlias| match verified_stmt(query) {
-            Statement::ExplainTable {
-                describe_alias,
-                hive_format,
-                table_name,
-            } => {
-                assert_eq!(describe_alias, expected_describe_alias);
-                assert_eq!(hive_format, None);
-                assert_eq!("test_identifier", table_name.to_string());
+        |query: &str, expected_describe_alias: DescribeAlias, expected_table_keyword| {
+            match verified_stmt(query) {
+                Statement::ExplainTable {
+                    describe_alias,
+                    hive_format,
+                    has_table_keyword,
+                    table_name,
+                } => {
+                    assert_eq!(describe_alias, expected_describe_alias);
+                    assert_eq!(hive_format, None);
+                    assert_eq!(has_table_keyword, expected_table_keyword);
+                    assert_eq!("test_identifier", table_name.to_string());
+                }
+                _ => panic!("Unexpected Statement, must be ExplainTable"),
             }
-            _ => panic!("Unexpected Statement, must be ExplainTable"),
         };
 
-    validate_explain("EXPLAIN test_identifier", DescribeAlias::Explain);
-    validate_explain("DESCRIBE test_identifier", DescribeAlias::Describe);
+    validate_explain("EXPLAIN test_identifier", DescribeAlias::Explain, false);
+    validate_explain("DESCRIBE test_identifier", DescribeAlias::Describe, false);
+    validate_explain("DESC test_identifier", DescribeAlias::Desc, false);
+    validate_explain(
+        "EXPLAIN TABLE test_identifier",
+        DescribeAlias::Explain,
+        true,
+    );
+    validate_explain(
+        "DESCRIBE TABLE test_identifier",
+        DescribeAlias::Describe,
+        true,
+    );
+    validate_explain("DESC TABLE test_identifier", DescribeAlias::Desc, true);
 }
 
 #[test]
 fn explain_describe() {
     verified_stmt("DESCRIBE test.table");
+    verified_stmt("DESCRIBE TABLE test.table");
 }
 
 #[test]
 fn explain_desc() {
     verified_stmt("DESC test.table");
+    verified_stmt("DESC TABLE test.table");
 }
 
 #[test]