diff --git a/types/sqlanywhere/index.d.ts b/types/sqlanywhere/index.d.ts
index d56bfb7993..148babd6ec 100644
--- a/types/sqlanywhere/index.d.ts
+++ b/types/sqlanywhere/index.d.ts
@@ -12,16 +12,16 @@ export interface SybaseConnection {
     close(cb: (err?: Error) => void): void;
     disconnect(cb: (err?: Error) => void): void;
     connected(): boolean;
-    exec(query: string, cb: (err: Error | undefined, result: any) => void);
+    exec(query: string, cb: (err: Error | undefined, result: any) => void): void;
     exec(
         query: string,
         placeholders: any[],
         cb: (err: Error | undefined, result: any) => void
-    );
+    ): void;
     prepare(
         query: string,
         cb: (err: Error | undefined, stmt: Statement) => void
-    );
+    ): void;
     prepare(query: string): Statement;
     commit(cb: (err: Error | undefined) => void): void;
     rollback(cb: (err: Error | undefined) => void): void;
@@ -37,7 +37,7 @@ export interface ConnectionParameters {
 }
 
 export interface Statement {
-    exec(args: any[], cb: (err: Error | undefined, rows: any[]) => void);
+    exec(args: any[], cb: (err: Error | undefined, rows: any[]) => void): void;
     exec(args: any[]): any[];
     getMoreResults(): any[];
     drop(cb: (err: Error | undefined) => void): void;