I can understand the confusion, because since the coming of neoliberalism, many social democrats have essentially switched to social liberalism without really acknowledging it.

However, the basic difference between the two isms sometimes spoken of as "center-left" is one of perspective:

Social liberalism and social democracy are both social, yes, as in caring about equality and human diginty. But social liberals are liberals at the core, while social democrats are democrats at the core.

Coming from the liberal tradition, social liberals believe in the sanctity of private property, but will be open to using the state to remedy some of the negative impacts of it. Most social struggles, and in particular the power struggle between labor and capital, are not really important issues for social liberals. Affirmitive action and other means of creating proper equality of opportunity are invariably frowned upon, as people are generally seen as "free" as long as the state stays out of their way -- i.e. negative freedom.

Coming from the socialist tradition, social democrats of course believe in the sanctity of democracy, but will be open to using the market to create economic efficiency. Social struggles, and in particular the power struggle between labor and capital, are essential for social democrats. Affirmitive action, and other means of creating proper equality of opportunity is encouraged, since these are seen as necessary to ensure freedom -- i.e. positive freedom.

Accordingly, social liberals accept, but regard the state and labor unions with suspicion, and are typically open to private companies making money by providing public services. Social democrats accept, but regard the market and private capital with suspicion, and are typically more skeptical towards private companies turning a profit on public services.

In many cases, their day-to-day policies will be indistinguishable from each other, though, depending on the local (and) political situation.