chore(query): alternative to tbl_name FROM db_name syntax is db_name.tbl_name (#17848)

Author: TCeason

src/query/ast/src/parser/statement.rs

@@ -786,20 +786,37 @@ pub fn statement_body(i: Input) -> IResult<Statement> {
             })
         },
     );
+
+    pub fn from_tables(i: Input) -> IResult<(Option<Identifier>, Option<Identifier>, Identifier)> {
+        let from_dot_table = map(
+            rule! {
+               ( FROM | IN ) ~ ^#dot_separated_idents_1_to_3
+            },
+            |(_, (catalog, database, table))| (catalog, database, table),
+        );
+
+        let from_table = map(
+            rule! {
+                ( FROM | IN ) ~ #ident
+                ~ ( FROM | IN ) ~ ^#dot_separated_idents_1_to_2
+            },
+            |(_, table, _, (catalog, database))| (catalog, Some(database), table),
+        );
+
+        rule!(
+            #from_table
+            | #from_dot_table
+        )(i)
+    }
+
     let show_columns = map(
         rule! {
             SHOW
             ~ FULL? ~ COLUMNS
-            ~ ( FROM | IN ) ~ #ident
-            ~ (( FROM | IN ) ~ ^#dot_separated_idents_1_to_2)?
+            ~ #from_tables
             ~ #show_limit?
         },
-        |(_, opt_full, _, _, table, ctl_db, limit)| {
-            let (catalog, database) = match ctl_db {
-                Some((_, (Some(c), d))) => (Some(c), Some(d)),
-                Some((_, (None, d))) => (None, Some(d)),
-                _ => (None, None),
-            };
+        |(_, opt_full, _, (catalog, database, table), limit)| {
             Statement::ShowColumns(ShowColumnsStmt {
                 catalog,
                 database,

src/query/ast/tests/it/parser.rs

@@ -106,7 +106,9 @@ fn test_statement() {
         r#"show full tables from ctl.db"#,
         r#"show full columns in t in db"#,
         r#"show columns in t from ctl.db"#,
+        r#"show columns from ctl.db.t"#,
         r#"show full columns from t from db like 'id%'"#,
+        r#"show full columns from db.t like 'id%'"#,
         r#"show processlist like 't%' limit 2;"#,
         r#"show processlist where database='default' limit 2;"#,
         r#"show create table a.b;"#,
@@ -970,6 +972,7 @@ fn test_statement_error() {
         r#"CALL system$test(a"#,
         r#"show settings ilike 'enable%'"#,
         r#"PRESIGN INVALID @my_stage/path/to/file"#,
+        r#"show columns from db1.t from ctl.db"#,
         r#"SELECT c a as FROM t"#,
         r#"SELECT c a as b FROM t"#,
         r#"SELECT top -1 c a as b FROM t"#,

src/query/ast/tests/it/testdata/stmt-error.txt

@@ -474,6 +474,16 @@ error:
   | while parsing `PRESIGN [{DOWNLOAD | UPLOAD}] <location> [EXPIRE = 3600]`
 
 
+---------- Input ----------
+show columns from db1.t from ctl.db
+---------- Output ---------
+error: 
+  --> SQL:1:25
+  |
+1 | show columns from db1.t from ctl.db
+  |                         ^^^^ unexpected `from`, expecting `FORMAT`, `.`, `LIKE`, `WHERE`, or `;`
+
+
 ---------- Input ----------
 SELECT c a as FROM t
 ---------- Output ---------

src/query/ast/tests/it/testdata/stmt.txt

@@ -490,6 +490,47 @@ ShowColumns(
 )
 
 
+---------- Input ----------
+show columns from ctl.db.t
+---------- Output ---------
+SHOW COLUMNS FROM t FROM ctl.db
+---------- AST ------------
+ShowColumns(
+    ShowColumnsStmt {
+        catalog: Some(
+            Identifier {
+                span: Some(
+                    18..21,
+                ),
+                name: "ctl",
+                quote: None,
+                ident_type: None,
+            },
+        ),
+        database: Some(
+            Identifier {
+                span: Some(
+                    22..24,
+                ),
+                name: "db",
+                quote: None,
+                ident_type: None,
+            },
+        ),
+        table: Identifier {
+            span: Some(
+                25..26,
+            ),
+            name: "t",
+            quote: None,
+            ident_type: None,
+        },
+        full: false,
+        limit: None,
+    },
+)
+
+
 ---------- Input ----------
 show full columns from t from db like 'id%'
 ---------- Output ---------
@@ -526,6 +567,42 @@ ShowColumns(
 )
 
 
+---------- Input ----------
+show full columns from db.t like 'id%'
+---------- Output ---------
+SHOW FULL COLUMNS FROM t FROM db LIKE 'id%'
+---------- AST ------------
+ShowColumns(
+    ShowColumnsStmt {
+        catalog: None,
+        database: Some(
+            Identifier {
+                span: Some(
+                    23..25,
+                ),
+                name: "db",
+                quote: None,
+                ident_type: None,
+            },
+        ),
+        table: Identifier {
+            span: Some(
+                26..27,
+            ),
+            name: "t",
+            quote: None,
+            ident_type: None,
+        },
+        full: true,
+        limit: Some(
+            Like {
+                pattern: "id%",
+            },
+        ),
+    },
+)
+
+
 ---------- Input ----------
 show processlist like 't%' limit 2;
 ---------- Output ---------

tests/sqllogictests/suites/base/06_show/06_0015_show_columns.test

@@ -14,7 +14,7 @@ statement ok
 CREATE TABLE showcolumn.t3(c1 int null default 4, c2 Datetime not null default '2022-02-02 12:00:00', c3 String not null Default 'c3') ENGINE = Null;
 
 query TTTTTT
-SHOW COLUMNS FROM t3 FROM showcolumn
+SHOW COLUMNS FROM default.showcolumn.t3
 ----
 c1 INT YES 4 NULL NULL
 c2 TIMESTAMP NO '2022-02-02 12:00:00.000000' NULL NULL