Support DESCRIBE TABLE syntax (#183)

Author: dejanmltc

parser/ast.go

@@ -8338,6 +8338,7 @@ func (s *ShowStmt) Accept(visitor ASTVisitor) error {
 type DescribeStmt struct {
 DescribePos Pos
 StatementEnd Pos
+DescribeType string // e.g., "TABLE", empty if not used
 Target *TableIdentifier
 }
 
@@ -8352,6 +8353,10 @@ func (d *DescribeStmt) End() Pos {
 func (d *DescribeStmt) String() string {
 var builder strings.Builder
 builder.WriteString("DESCRIBE ")
+if d.DescribeType != "" {
+builder.WriteString(d.DescribeType)
+builder.WriteString(" ")
+}
 builder.WriteString(d.Target.String())
 return builder.String()
 }

parser/parser_table.go

@@ -1308,6 +1308,13 @@ func (p *Parser) parseDescribeStmt(pos Pos) (*DescribeStmt, error) {
 }
 _ = p.lexer.consumeToken()
 
+// TABLE keyword is optional after DESC/DESCRIBE
+var describeType string
+if p.matchKeyword(KeywordTable) {
+_ = p.lexer.consumeToken()
+describeType = "TABLE"
+}
+
 tableIdent, err := p.parseTableIdentifier(p.Pos())
 if err != nil {
 return nil, err
@@ -1316,6 +1323,7 @@ func (p *Parser) parseDescribeStmt(pos Pos) (*DescribeStmt, error) {
 return &DescribeStmt{
 DescribePos: pos,
 StatementEnd: tableIdent.End(),
+DescribeType: describeType,
 Target: tableIdent,
 }, nil
 }

parser/testdata/ddl/desc_table_with_table_keyword.sql

@@ -0,0 +1 @@
+DESC TABLE mytable

parser/testdata/ddl/desc_table.sql renamed to parser/testdata/ddl/desc_table_without_table_keyword.sql

@@ -0,0 +1 @@
+DESCRIBE TABLE mytable

parser/testdata/ddl/describe_table_with_table_keyword.sql

@@ -1,5 +1,5 @@
 -- Origin SQL:
-DESC mytable
+DESC TABLE mytable
 
 -- Format SQL:
-DESCRIBE mytable;
+DESCRIBE TABLE mytable;

parser/testdata/ddl/describe_table.sql renamed to parser/testdata/ddl/describe_table_without_table_keyword.sql

@@ -0,0 +1,5 @@
+-- Origin SQL:
+DESC TABLE mytable
+
+-- Format SQL:
+DESCRIBE TABLE mytable;

parser/testdata/ddl/format/desc_table.sql

@@ -0,0 +1,5 @@
+-- Origin SQL:
+DESC mytable
+
+-- Format SQL:
+DESCRIBE mytable;

parser/testdata/ddl/format/desc_table_with_table_keyword.sql

@@ -1,5 +1,5 @@
 -- Origin SQL:
-DESCRIBE mytable
+DESCRIBE TABLE mytable
 
 -- Format SQL:
-DESCRIBE mytable;
+DESCRIBE TABLE mytable;