This paper deals with a class of time inconsistent stochastic linear quadratic optimal control problems in Markovian framework. Three notions, i.e., closed-loop equilibrium strategies, open-loop equilibrium controls and open-loop equilibrium strategies, are characterized in unified manners. These results indicate clearer and deeper distinctions among these notions. For example, in particular time consistent setting, the open-loop equilibrium controls are fully characterized by first-order, second-ordernecessaryoptimalityconditions, and are not optimal in general, while the closed-loop equilibrium controls naturally reduce into closed-loopoptimalcontrols.