How to get Theorem numbering as per section.subsection.subsubsection.number in Latex

Question

I'm not very familiar to Latex. The numbering of my theorems, definitions, remarks etc. appears like 1.0.0.1 for first definition. I don't want zeroes to appear if there are no subsections or subsubsections. Here is what Have in preamble

\documentclass[12pt]{article}
\usepackage{amsthm,amsmath}
\usepackage{amscd}
\usepackage{hyperref}
\usepackage[all]{xypic}
\usepackage{mathtools}
\usepackage{xcolor}
\usepackage[utf8]{inputenc}
\usepackage{amssymb,mathrsfs}
\usepackage{hyperref}
\usepackage[all]{xypic}
\usepackage{times}
\usepackage{inputenc}
\usepackage{lipsum}
\usepackage{titlesec}
\DeclareUnicodeCharacter{0308}{HERE!HERE!}
\setcounter{MaxMatrixCols}{10}

\newtheorem{lemma}{Lemma}[subsubsection]
\newtheorem{corollary}[lemma]{Corollary}
\newtheorem{fact}[lemma]{Fact}
\newtheorem{theorem}[lemma]{Theorem}
\newtheorem{proposition}[lemma]{Proposition}
\newtheorem{definition}[lemma]{Definition}
\newtheorem{remark}[lemma]{Remark}
\newtheorem{example}[lemma]{Example}
\newtheorem{examples}[lemma]{Examples}
\newtheorem{question}[lemma]{Question}

Please help.

Edit: In my first section (for example), there is no subsection, so I want numbering as 1.1, 1.2 and so on and not as 1.0.0.1, 1.0.0.2 etc. In my second section I have a subsection but no subsubsection, there I want theorem numbering to be like "Theorem 2.1.1" and so on. I want four-digit numbering to start when there is a subsubsection". I hope my question is clear now.

Answer 1

I really would not encourage this way of doing. But quick and dirty you may try

\documentclass[12pt]{article}
\usepackage{amsthm}
\usepackage{mathtools}
\newtheorem{lemma}{Lemma}[subsubsection]
\newcounter{lemmaaux}
\setcounter{lemmaaux}{0}
\begin{document}
\section{first}
\counterwithin{lemma}{section}
\begin{lemma}\addtocounter{lemmaaux}{1}
My nice lemma
\end{lemma}
\subsection{The fist sub}
\counterwithin{lemma}{subsection}\setcounter{lemma}{\thelemmaaux}
\begin{lemma}\addtocounter{lemmaaux}{1}
My nice second lemma
\end{lemma}
\subsubsection{The fist subsub}
\counterwithin{lemma}{subsubsection}\setcounter{lemma}{\thelemmaaux}
\begin{lemma}\addtocounter{lemmaaux}{1}
My new lemma
\end{lemma}
\section{second}
\counterwithin{lemma}{section}\setcounter{lemma}{\thelemmaaux}
\begin{lemma}\addtocounter{lemmaaux}{1}
My nice third lemma
\end{lemma}
\subsection{The second sub}
\counterwithin{lemma}{subsection}\setcounter{lemma}{\thelemmaaux}
\begin{lemma}\addtocounter{lemmaaux}{1}
My nice fourth lemma
\end{lemma}
\end{document}