feat(sqlite): add SQLite support to format tests (#4207)

Implements comprehensive formatting support for SQLite SQL statements,
enabling round-trip format testing similar to MySQL. Key changes:

**New SQLite Formatter:**
- Add format.go implementing Formatter interface for SQLite dialect
- Support SQLite-specific named parameter syntax (`:name` instead of `@name`)

**AST Formatting Fixes:**
- Add `NamedParam` method to Formatter interface for dialect-specific named params
- Fix `CollateExpr` missing Format method for COLLATE clause support
- Add `DefaultValues` field to InsertStmt for INSERT DEFAULT VALUES syntax
- Fix table function argument conversion (e.g., json_each())

**SQLite Parser Improvements:**
- Fix BoolExpr Boolop field for AND/OR expressions
- Add EXISTS/NOT EXISTS subquery handling via SubLink nodes
- Add unary expression support (NOT operator)
- Fix NULL literal conversion in COALESCE expressions

**Test Updates:**
- Add SQLite case to fmt_test.go with case-insensitive fingerprinting
- Regenerate expected output for select_exists/select_not_exists tests
  (EXISTS now correctly returns bool instead of int64)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude <noreply@anthropic.com>

Author: kyleconroy

internal/endtoend/fmt_test.go

@@ -13,6 +13,7 @@ import (
 	"github.com/sqlc-dev/sqlc/internal/debug"
 	"github.com/sqlc-dev/sqlc/internal/engine/dolphin"
 	"github.com/sqlc-dev/sqlc/internal/engine/postgresql"
+	"github.com/sqlc-dev/sqlc/internal/engine/sqlite"
 	"github.com/sqlc-dev/sqlc/internal/sql/ast"
 	"github.com/sqlc-dev/sqlc/internal/sql/format"
 )
@@ -79,6 +80,22 @@ func TestFormat(t *testing.T) {
 					}
 					return ast.Format(stmts[0].Raw, mysqlParser), nil
 				}
+			case config.EngineSQLite:
+				sqliteParser := sqlite.NewParser()
+				parse = sqliteParser
+				formatter = sqliteParser
+				// For SQLite, we use the same "round-trip" fingerprint strategy as MySQL:
+				// parse the SQL, format it, and return the formatted string.
+				fingerprint = func(sql string) (string, error) {
+					stmts, err := sqliteParser.Parse(strings.NewReader(sql))
+					if err != nil {
+						return "", err
+					}
+					if len(stmts) == 0 {
+						return "", nil
+					}
+					return strings.ToLower(ast.Format(stmts[0].Raw, sqliteParser)), nil
+				}
 			default:
 				// Skip unsupported engines
 				return

internal/endtoend/testdata/select_exists/sqlite/go/query.sql.go

@@ -29,6 +29,13 @@ func (p *Parser) Param(n int) string {
 	return "?"
 }
 
+// NamedParam returns the named parameter placeholder for the given name.
+// MySQL doesn't have native named parameters, so we use ? (positional).
+// The actual parameter names are handled by sqlc's rewrite phase.
+func (p *Parser) NamedParam(name string) string {
+	return "?"
+}
+
 // Cast returns a type cast expression.
 // MySQL uses CAST(expr AS type) syntax.
 func (p *Parser) Cast(arg, typeName string) string {

internal/endtoend/testdata/select_not_exists/sqlite/go/query.sql.go

@@ -64,6 +64,12 @@ func (p *Parser) Param(n int) string {
 	return fmt.Sprintf("$%d", n)
 }
 
+// NamedParam returns the named parameter placeholder for the given name.
+// PostgreSQL/sqlc uses @name syntax.
+func (p *Parser) NamedParam(name string) string {
+	return "@" + name
+}
+
 // Cast returns a type cast expression.
 // PostgreSQL uses expr::type syntax.
 func (p *Parser) Cast(arg, typeName string) string {

internal/engine/dolphin/format.go

@@ -514,7 +514,10 @@ func (c *cc) convertMultiSelect_stmtContext(n *parser.Select_stmtContext) ast.No
 	limitCount, limitOffset := c.convertLimit_stmtContext(n.Limit_stmt())
 	selectStmt.LimitCount = limitCount
 	selectStmt.LimitOffset = limitOffset
-	selectStmt.WithClause = &ast.WithClause{Ctes: &ctes}
+	// Only set WithClause if there are CTEs
+	if len(ctes.Items) > 0 {
+		selectStmt.WithClause = &ast.WithClause{Ctes: &ctes}
+	}
 	return selectStmt
 }
 
@@ -759,6 +762,13 @@ func (c *cc) convertLiteral(n *parser.Expr_literalContext) ast.Node {
 				Location: n.GetStart().GetStart(),
 			}
 		}
+
+		if literal.NULL_() != nil {
+			return &ast.A_Const{
+				Val:      &ast.Null{},
+				Location: n.GetStart().GetStart(),
+			}
+		}
 	}
 	return todo("convertLiteral", n)
 }
@@ -776,8 +786,14 @@ func (c *cc) convertBinaryNode(n *parser.Expr_binaryContext) ast.Node {
 }
 
 func (c *cc) convertBoolNode(n *parser.Expr_boolContext) ast.Node {
+	var op ast.BoolExprType
+	if n.AND_() != nil {
+		op = ast.BoolExprTypeAnd
+	} else if n.OR_() != nil {
+		op = ast.BoolExprTypeOr
+	}
 	return &ast.BoolExpr{
-		// TODO: Set op
+		Boolop: op,
 		Args: &ast.List{
 			Items: []ast.Node{
 				c.convert(n.Expr(0)),
@@ -787,6 +803,49 @@ func (c *cc) convertBoolNode(n *parser.Expr_boolContext) ast.Node {
 	}
 }
 
+func (c *cc) convertUnaryExpr(n *parser.Expr_unaryContext) ast.Node {
+	op := n.Unary_operator()
+	if op == nil {
+		return c.convert(n.Expr())
+	}
+
+	// Get the inner expression
+	expr := c.convert(n.Expr())
+
+	// Check the operator type
+	if opCtx, ok := op.(*parser.Unary_operatorContext); ok {
+		if opCtx.NOT_() != nil {
+			// NOT expression
+			return &ast.BoolExpr{
+				Boolop: ast.BoolExprTypeNot,
+				Args: &ast.List{
+					Items: []ast.Node{expr},
+				},
+			}
+		}
+		if opCtx.MINUS() != nil {
+			// Negative number: -expr
+			return &ast.A_Expr{
+				Name: &ast.List{Items: []ast.Node{&ast.String{Str: "-"}}},
+				Rexpr: expr,
+			}
+		}
+		if opCtx.PLUS() != nil {
+			// Positive number: +expr (just return expr)
+			return expr
+		}
+		if opCtx.TILDE() != nil {
+			// Bitwise NOT: ~expr
+			return &ast.A_Expr{
+				Name: &ast.List{Items: []ast.Node{&ast.String{Str: "~"}}},
+				Rexpr: expr,
+			}
+		}
+	}
+
+	return expr
+}
+
 func (c *cc) convertParam(n *parser.Expr_bindContext) ast.Node {
 	if n.NUMBERED_BIND_PARAMETER() != nil {
 		// Parameter numbers start at one
@@ -816,7 +875,52 @@ func (c *cc) convertParam(n *parser.Expr_bindContext) ast.Node {
 }
 
 func (c *cc) convertInSelectNode(n *parser.Expr_in_selectContext) ast.Node {
-	return c.convert(n.Select_stmt())
+	// Check if this is EXISTS or NOT EXISTS
+	if n.EXISTS_() != nil {
+		linkType := ast.EXISTS_SUBLINK
+		sublink := &ast.SubLink{
+			SubLinkType: linkType,
+			Subselect:   c.convert(n.Select_stmt()),
+		}
+		if n.NOT_() != nil {
+			// NOT EXISTS is represented as a BoolExpr NOT wrapping the EXISTS
+			return &ast.BoolExpr{
+				Boolop: ast.BoolExprTypeNot,
+				Args: &ast.List{
+					Items: []ast.Node{sublink},
+				},
+			}
+		}
+		return sublink
+	}
+
+	// Check if this is an IN/NOT IN expression: expr IN (SELECT ...)
+	if n.IN_() != nil && len(n.AllExpr()) > 0 {
+		linkType := ast.ANY_SUBLINK
+		sublink := &ast.SubLink{
+			SubLinkType: linkType,
+			Testexpr:    c.convert(n.Expr(0)),
+			Subselect:   c.convert(n.Select_stmt()),
+		}
+		if n.NOT_() != nil {
+			return &ast.A_Expr{
+				Kind:  ast.A_Expr_Kind_OP,
+				Name:  &ast.List{Items: []ast.Node{&ast.String{Str: "NOT IN"}}},
+				Lexpr: c.convert(n.Expr(0)),
+				Rexpr: &ast.SubLink{
+					SubLinkType: ast.EXPR_SUBLINK,
+					Subselect:   c.convert(n.Select_stmt()),
+				},
+			}
+		}
+		return sublink
+	}
+
+	// Plain subquery in parentheses (SELECT ...)
+	return &ast.SubLink{
+		SubLinkType: ast.EXPR_SUBLINK,
+		Subselect:   c.convert(n.Select_stmt()),
+	}
 }
 
 func (c *cc) convertReturning_caluseContext(n parser.IReturning_clauseContext) *ast.List {
@@ -887,12 +991,8 @@ func (c *cc) convertInsert_stmtContext(n *parser.Insert_stmtContext) ast.Node {
 	}
 
 	if hasDefaultValues {
-		// For DEFAULT VALUES, create an empty select statement
-		insert.SelectStmt = &ast.SelectStmt{
-			FromClause:  &ast.List{},
-			TargetList:  &ast.List{},
-			ValuesLists: &ast.List{Items: []ast.Node{&ast.List{}}}, // Single empty values list
-		}
+		// For DEFAULT VALUES, set the flag instead of creating an empty values list
+		insert.DefaultValues = true
 	} else if n.Select_stmt() != nil {
 		if ss, ok := c.convert(n.Select_stmt()).(*ast.SelectStmt); ok {
 			ss.ValuesLists = &ast.List{}
@@ -976,6 +1076,11 @@ func (c *cc) convertTablesOrSubquery(n []parser.ITable_or_subqueryContext) []ast
 			tables = append(tables, rv)
 		} else if from.Table_function_name() != nil {
 			rel := from.Table_function_name().GetText()
+			// Convert function arguments
+			var args []ast.Node
+			for _, expr := range from.AllExpr() {
+				args = append(args, c.convert(expr))
+			}
 			rf := &ast.RangeFunction{
 				Functions: &ast.List{
 					Items: []ast.Node{
@@ -989,7 +1094,7 @@ func (c *cc) convertTablesOrSubquery(n []parser.ITable_or_subqueryContext) []ast
 								},
 							},
 							Args: &ast.List{
-								Items: []ast.Node{&ast.TODO{}},
+								Items: args,
 							},
 							Location: from.GetStart().GetStart(),
 						},
@@ -1189,6 +1294,9 @@ func (c *cc) convert(node node) ast.Node {
 	case *parser.Expr_binaryContext:
 		return c.convertBinaryNode(n)
 
+	case *parser.Expr_unaryContext:
+		return c.convertUnaryExpr(n)
+
 	case *parser.Expr_in_selectContext:
 		return c.convertInSelectNode(n)
 

internal/engine/postgresql/reserved.go

@@ -0,0 +1,35 @@
+package sqlite
+
+// QuoteIdent returns a quoted identifier if it needs quoting.
+// SQLite uses double quotes for quoting identifiers (SQL standard),
+// though backticks are also supported for MySQL compatibility.
+func (p *Parser) QuoteIdent(s string) string {
+	// For now, don't quote - return as-is
+	return s
+}
+
+// TypeName returns the SQL type name for the given namespace and name.
+func (p *Parser) TypeName(ns, name string) string {
+	if ns != "" {
+		return ns + "." + name
+	}
+	return name
+}
+
+// Param returns the parameter placeholder for the given number.
+// SQLite uses ? for positional parameters.
+func (p *Parser) Param(n int) string {
+	return "?"
+}
+
+// NamedParam returns the named parameter placeholder for the given name.
+// SQLite uses :name syntax for named parameters.
+func (p *Parser) NamedParam(name string) string {
+	return ":" + name
+}
+
+// Cast returns a type cast expression.
+// SQLite uses CAST(expr AS type) syntax.
+func (p *Parser) Cast(arg, typeName string) string {
+	return "CAST(" + arg + " AS " + typeName + ")"
+}

internal/engine/sqlite/convert.go

@@ -12,10 +12,36 @@ func (n *A_Expr) Pos() int {
 	return n.Location
 }
 
+// isNamedParam returns true if this A_Expr represents a named parameter (@name)
+// and extracts the parameter name if so.
+func (n *A_Expr) isNamedParam() (string, bool) {
+	if n.Name == nil || len(n.Name.Items) != 1 {
+		return "", false
+	}
+	s, ok := n.Name.Items[0].(*String)
+	if !ok || s.Str != "@" {
+		return "", false
+	}
+	if set(n.Lexpr) || !set(n.Rexpr) {
+		return "", false
+	}
+	if nameStr, ok := n.Rexpr.(*String); ok {
+		return nameStr.Str, true
+	}
+	return "", false
+}
+
 func (n *A_Expr) Format(buf *TrackedBuffer) {
 	if n == nil {
 		return
 	}
+
+	// Check for named parameter first (works regardless of Kind)
+	if name, ok := n.isNamedParam(); ok {
+		buf.WriteString(buf.NamedParam(name))
+		return
+	}
+
 	switch n.Kind {
 	case A_Expr_Kind_IN:
 		buf.astFormat(n.Lexpr)
@@ -64,32 +90,8 @@ func (n *A_Expr) Format(buf *TrackedBuffer) {
 		buf.WriteString(", ")
 		buf.astFormat(n.Rexpr)
 		buf.WriteString(")")
-	case A_Expr_Kind_OP:
-		// Check if this is a named parameter (@name)
-		opName := ""
-		if n.Name != nil && len(n.Name.Items) == 1 {
-			if s, ok := n.Name.Items[0].(*String); ok {
-				opName = s.Str
-			}
-		}
-		if opName == "@" && !set(n.Lexpr) && set(n.Rexpr) {
-			// Named parameter: @name (no space after @)
-			buf.WriteString("@")
-			buf.astFormat(n.Rexpr)
-		} else {
-			// Standard binary operator
-			if set(n.Lexpr) {
-				buf.astFormat(n.Lexpr)
-				buf.WriteString(" ")
-			}
-			buf.astFormat(n.Name)
-			if set(n.Rexpr) {
-				buf.WriteString(" ")
-				buf.astFormat(n.Rexpr)
-			}
-		}
 	default:
-		// Fallback for other cases
+		// Standard operator (including A_Expr_Kind_OP)
 		if set(n.Lexpr) {
 			buf.astFormat(n.Lexpr)
 			buf.WriteString(" ")