parser: Generate correct types for SELECT EXISTS

internal/dinosql/parser.go

@@ -439,6 +439,8 @@ func parseQuery(c core.Catalog, stmt nodes.Node, source string, rewriteParameter
 		return nil, errUnsupportedStatementType
 	}
 
+	// spew.Dump(stmt)
+
 	rawSQL, err := pluckQuery(source, raw)
 	if err != nil {
 		return nil, err
@@ -942,6 +944,18 @@ func outputColumns(qc *QueryCatalog, node nodes.Node) ([]core.Column, error) {
 				cols = append(cols, core.Column{Name: name, DataType: "any"})
 			}
 
+		case nodes.SubLink:
+			name := "exists"
+			if res.Name != nil {
+				name = *res.Name
+			}
+			switch n.SubLinkType {
+			case nodes.EXISTS_SUBLINK:
+				cols = append(cols, core.Column{Name: name, DataType: "bool", NotNull: true})
+			default:
+				cols = append(cols, core.Column{Name: name, DataType: "any", NotNull: false})
+			}
+
 		case nodes.TypeCast:
 			if n.TypeName == nil {
 				return nil, errors.New("no type name type cast")

internal/endtoend/testdata/select_exists/query.sql

@@ -0,0 +1,12 @@
+CREATE TABLE bar (id serial not null);
+
+-- name: BarExists :one
+SELECT
+    EXISTS (
+        SELECT
+            1
+        FROM
+            bar
+        where
+            id = $1
+    );

internal/endtoend/testdata/select_exists/sqlc.json

@@ -0,0 +1,9 @@
+{
+  "version": "1",
+  "packages": [{
+    "path": "go",
+	"name": "querytest",
+	"schema": "query.sql",
+	"queries": "query.sql"
+  }]
+}