Add more T-SQL statement support and enable 8 additional tests

- Add TRUNCATE TABLE with partition support
- Add trivial statements (USE, KILL, CHECKPOINT, RECONFIGURE, SHUTDOWN, SETUSER, LINENO)
- Add RAISERROR statement with WITH options
- Add GlobalVariableExpression for @@variables
- Add BooleanParenthesisExpression for parenthesized conditions
- Add BooleanIsNullExpression for IS NULL/IS NOT NULL
- Enable 8 new tests: TruncatePartitions120 (x2), TrivialStatementTests (x2),
  WhileStatementTests (x2), RaiseErrorStatementTests (x2)

Author: claude

ast/boolean_is_null_expression.go

@@ -0,0 +1,10 @@
+package ast
+
+// BooleanIsNullExpression represents an IS NULL / IS NOT NULL expression.
+type BooleanIsNullExpression struct {
+	IsNot      bool
+	Expression ScalarExpression
+}
+
+func (b *BooleanIsNullExpression) node()              {}
+func (b *BooleanIsNullExpression) booleanExpression() {}

ast/boolean_parenthesis_expression.go

@@ -0,0 +1,9 @@
+package ast
+
+// BooleanParenthesisExpression represents a parenthesized boolean expression.
+type BooleanParenthesisExpression struct {
+	Expression BooleanExpression
+}
+
+func (b *BooleanParenthesisExpression) node()              {}
+func (b *BooleanParenthesisExpression) booleanExpression() {}

ast/global_variable_expression.go

@@ -0,0 +1,9 @@
+package ast
+
+// GlobalVariableExpression represents a global variable like @@IDENTITY, @@ERROR, etc.
+type GlobalVariableExpression struct {
+	Name string
+}
+
+func (g *GlobalVariableExpression) node()             {}
+func (g *GlobalVariableExpression) scalarExpression() {}

ast/raiserror_statement.go

@@ -0,0 +1,13 @@
+package ast
+
+// RaiseErrorStatement represents a RAISERROR statement.
+type RaiseErrorStatement struct {
+	FirstParameter     ScalarExpression
+	SecondParameter    ScalarExpression
+	ThirdParameter     ScalarExpression
+	OptionalParameters []ScalarExpression
+	RaiseErrorOptions  string
+}
+
+func (r *RaiseErrorStatement) node()      {}
+func (r *RaiseErrorStatement) statement() {}

ast/trivial_statements.go

@@ -0,0 +1,52 @@
+package ast
+
+type UseStatement struct {
+	DatabaseName *Identifier `json:"DatabaseName,omitempty"`
+}
+
+func (u *UseStatement) node()      {}
+func (u *UseStatement) statement() {}
+
+type KillStatement struct {
+	Parameter      ScalarExpression `json:"Parameter,omitempty"`
+	WithStatusOnly bool             `json:"WithStatusOnly"`
+}
+
+func (k *KillStatement) node()      {}
+func (k *KillStatement) statement() {}
+
+type CheckpointStatement struct {
+	Duration ScalarExpression `json:"Duration,omitempty"`
+}
+
+func (c *CheckpointStatement) node()      {}
+func (c *CheckpointStatement) statement() {}
+
+type ReconfigureStatement struct {
+	WithOverride bool `json:"WithOverride"`
+}
+
+func (r *ReconfigureStatement) node()      {}
+func (r *ReconfigureStatement) statement() {}
+
+type ShutdownStatement struct {
+	WithNoWait bool `json:"WithNoWait"`
+}
+
+func (s *ShutdownStatement) node()      {}
+func (s *ShutdownStatement) statement() {}
+
+type SetUserStatement struct {
+	UserName    ScalarExpression `json:"UserName,omitempty"`
+	WithNoReset bool             `json:"WithNoReset"`
+}
+
+func (s *SetUserStatement) node()      {}
+func (s *SetUserStatement) statement() {}
+
+type LineNoStatement struct {
+	LineNo ScalarExpression `json:"LineNo,omitempty"`
+}
+
+func (l *LineNoStatement) node()      {}
+func (l *LineNoStatement) statement() {}

ast/truncate_table_statement.go

@@ -0,0 +1,14 @@
+package ast
+
+type TruncateTableStatement struct {
+	TableName       *SchemaObjectName           `json:"TableName,omitempty"`
+	PartitionRanges []*CompressionPartitionRange `json:"PartitionRanges,omitempty"`
+}
+
+func (t *TruncateTableStatement) node()      {}
+func (t *TruncateTableStatement) statement() {}
+
+type CompressionPartitionRange struct {
+	From ScalarExpression `json:"From,omitempty"`
+	To   ScalarExpression `json:"To,omitempty"`
+}

parser/lexer.go

@@ -91,6 +91,7 @@ const (
 	TokenValues
 	TokenDefault
 	TokenNull
+	TokenIs
 	TokenExec
 	TokenExecute
 	TokenOver
@@ -157,6 +158,16 @@ const (
 	TokenMove
 	TokenConversation
 	TokenGet
+	TokenUse
+	TokenKill
+	TokenCheckpoint
+	TokenReconfigure
+	TokenOverride
+	TokenShutdown
+	TokenSetuser
+	TokenLineno
+	TokenStatusonly
+	TokenNoreset
 )
 
 // Token represents a lexical token.
@@ -513,6 +524,7 @@ var keywords = map[string]TokenType{
 	"VALUES":        TokenValues,
 	"DEFAULT":       TokenDefault,
 	"NULL":          TokenNull,
+	"IS":            TokenIs,
 	"EXEC":          TokenExec,
 	"EXECUTE":       TokenExecute,
 	"OVER":          TokenOver,
@@ -566,6 +578,16 @@ var keywords = map[string]TokenType{
 	"MOVE":          TokenMove,
 	"CONVERSATION":  TokenConversation,
 	"GET":           TokenGet,
+	"USE":           TokenUse,
+	"KILL":          TokenKill,
+	"CHECKPOINT":    TokenCheckpoint,
+	"RECONFIGURE":   TokenReconfigure,
+	"OVERRIDE":      TokenOverride,
+	"SHUTDOWN":      TokenShutdown,
+	"SETUSER":       TokenSetuser,
+	"LINENO":        TokenLineno,
+	"STATUSONLY":    TokenStatusonly,
+	"NORESET":       TokenNoreset,
 }
 
 func lookupKeyword(ident string) TokenType {