Add support of PROJECTION column in CREATE TABLE (#178)

Author: git-hulk

parser/ast.go

@@ -786,9 +786,10 @@ func (p *ProjectionSelectStmt) Accept(visitor ASTVisitor) error {
 }
 
 type TableProjection struct {
-	ProjectionPos Pos
-	Identifier    *NestedIdentifier
-	Select        *ProjectionSelectStmt
+	IncludeProjectionKeyword bool
+	ProjectionPos            Pos
+	Identifier               *NestedIdentifier
+	Select                   *ProjectionSelectStmt
 }
 
 func (t *TableProjection) Pos() Pos {
@@ -801,6 +802,9 @@ func (t *TableProjection) End() Pos {
 
 func (t *TableProjection) String() string {
 	var builder strings.Builder
+	if t.IncludeProjectionKeyword {
+		builder.WriteString("PROJECTION ")
+	}
 	builder.WriteString(t.Identifier.String())
 	builder.WriteString(" ")
 	builder.WriteString(t.Select.String())
@@ -5182,15 +5186,15 @@ func (c *CreateLiveView) Accept(visitor ASTVisitor) error {
 }
 
 type CreateDictionary struct {
-	CreatePos       Pos
-	StatementEnd    Pos
-	OrReplace       bool
-	Name            *TableIdentifier
-	IfNotExists     bool
-	UUID            *UUID
-	OnCluster       *ClusterClause
-	Schema          *DictionarySchemaClause
-	Engine          *DictionaryEngineClause
+	CreatePos    Pos
+	StatementEnd Pos
+	OrReplace    bool
+	Name         *TableIdentifier
+	IfNotExists  bool
+	UUID         *UUID
+	OnCluster    *ClusterClause
+	Schema       *DictionarySchemaClause
+	Engine       *DictionaryEngineClause
 }
 
 func (c *CreateDictionary) Type() string {
@@ -5395,13 +5399,13 @@ func (d *DictionaryAttribute) Accept(visitor ASTVisitor) error {
 }
 
 type DictionaryEngineClause struct {
-	EnginePos   Pos
-	PrimaryKey  *DictionaryPrimaryKeyClause
-	Source      *DictionarySourceClause
-	Lifetime    *DictionaryLifetimeClause
-	Layout      *DictionaryLayoutClause
-	Range       *DictionaryRangeClause
-	Settings    *SettingsClause
+	EnginePos  Pos
+	PrimaryKey *DictionaryPrimaryKeyClause
+	Source     *DictionarySourceClause
+	Lifetime   *DictionaryLifetimeClause
+	Layout     *DictionaryLayoutClause
+	Range      *DictionaryRangeClause
+	Settings   *SettingsClause
 }
 
 func (d *DictionaryEngineClause) Pos() Pos {
@@ -5432,7 +5436,7 @@ func (d *DictionaryEngineClause) End() Pos {
 
 func (d *DictionaryEngineClause) String() string {
 	var builder strings.Builder
-	
+
 	if d.PrimaryKey != nil {
 		builder.WriteString(d.PrimaryKey.String())
 	}
@@ -5595,7 +5599,7 @@ func (d *DictionarySourceClause) Accept(visitor ASTVisitor) error {
 type DictionaryArgExpr struct {
 	ArgPos Pos
 	Name   *Ident
-	Value  Expr  // can be Ident with optional parentheses or literal
+	Value  Expr // can be Ident with optional parentheses or literal
 }
 
 func (d *DictionaryArgExpr) Pos() Pos {
@@ -5630,7 +5634,7 @@ type DictionaryLifetimeClause struct {
 	LifetimePos Pos
 	Min         *NumberLiteral
 	Max         *NumberLiteral
-	Value       *NumberLiteral  // for simple LIFETIME(value) form
+	Value       *NumberLiteral // for simple LIFETIME(value) form
 	RParenPos   Pos
 }
 

parser/parser_alter.go

@@ -206,7 +206,12 @@ func (p *Parser) parseProjectionSelect(pos Pos) (*ProjectionSelectStmt, error) {
 	}, nil
 }
 
-func (p *Parser) parseTableProjection(pos Pos) (*TableProjection, error) {
+func (p *Parser) parseTableProjection(pos Pos, includeProjectionKeyword bool) (*TableProjection, error) {
+	if includeProjectionKeyword {
+		if err := p.expectKeyword(KeywordProjection); err != nil {
+			return nil, err
+		}
+	}
 	identifier, err := p.ParseNestedIdentifier(pos)
 	if err != nil {
 		return nil, err
@@ -216,9 +221,10 @@ func (p *Parser) parseTableProjection(pos Pos) (*TableProjection, error) {
 		return nil, err
 	}
 	return &TableProjection{
-		ProjectionPos: pos,
-		Identifier:    identifier,
-		Select:        selectExpr,
+		IncludeProjectionKeyword: includeProjectionKeyword,
+		ProjectionPos:            pos,
+		Identifier:               identifier,
+		Select:                   selectExpr,
 	}, nil
 }
 
@@ -231,7 +237,7 @@ func (p *Parser) parseAlterTableAddProjection(pos Pos) (*AlterTableAddProjection
 	if err != nil {
 		return nil, err
 	}
-	tableProjection, err := p.parseTableProjection(p.Pos())
+	tableProjection, err := p.parseTableProjection(p.Pos(), false)
 	if err != nil {
 		return nil, err
 	}

parser/parser_table.go

@@ -461,6 +461,12 @@ func (p *Parser) parseTableColumns() ([]Expr, error) {
 				Constraint:    ident,
 				Expr:          expr,
 			})
+		case p.matchKeyword(KeywordProjection):
+			projection, err := p.parseTableProjection(p.Pos(), true)
+			if err != nil {
+				return nil, err
+			}
+			columns = append(columns, projection)
 		default:
 			column, err := p.tryParseTableColumnExpr(p.Pos())
 			if err != nil {
@@ -1977,7 +1983,6 @@ func (p *Parser) parseDictionarySettingsClause(pos Pos) (*SettingsClause, error)
 
 	settings := &SettingsClause{SettingsPos: pos, ListEnd: pos}
 	items := make([]*SettingExprList, 0)
-	
 	// Parse first setting
 	expr, err := p.parseSettingsExprList(p.Pos())
 	if err != nil {

parser/testdata/ddl/create_table_with_projection.sql

@@ -0,0 +1,15 @@
+CREATE TABLE events
+(
+    `event_time` DateTime,
+    `event_id` UInt64,
+    `user_id` UInt64,
+    `huge_string` String,
+    PROJECTION order_by_user_id
+    (
+        SELECT
+            _part_offset
+        ORDER BY user_id
+    )
+)
+ENGINE = MergeTree()
+ORDER BY (event_id); 

parser/testdata/ddl/format/create_table_with_projection.sql

@@ -0,0 +1,19 @@
+-- Origin SQL:
+CREATE TABLE events
+(
+    `event_time` DateTime,
+    `event_id` UInt64,
+    `user_id` UInt64,
+    `huge_string` String,
+    PROJECTION order_by_user_id
+    (
+        SELECT
+            _part_offset
+        ORDER BY user_id
+    )
+)
+ENGINE = MergeTree()
+ORDER BY (event_id); 
+
+-- Format SQL:
+CREATE TABLE events (`event_time` DateTime, `event_id` UInt64, `user_id` UInt64, `huge_string` String, PROJECTION order_by_user_id (SELECT _part_offset ORDER BY user_id)) ENGINE = MergeTree() ORDER BY (event_id);

parser/testdata/ddl/output/alter_table_add_projection.sql.golden.json

@@ -18,6 +18,7 @@
         "StatementEnd": 140,
         "IfNotExists": true,
         "TableProjection": {
+          "IncludeProjectionKeyword": false,
           "ProjectionPos": 55,
           "Identifier": {
             "Ident": {