Select a single row
Click in any cell of that row. It is not necessary to select the content. The selected row is not highlighted.
Select more rows
Hold pressed the left mouse button, and drag horizontally or vertically above the cells. The content of selected rows is highlighted (if any). It is enough to select any cell of a row to have entire row selected. On the following screenshot, both rows are selected.
If you selecting more rows in an empty table, no highlighting takes place.
It is not possible to select more non adjacent rows.
To select all rows
Right-click in a table, point to Select, and then click Table Content.
See also
Select cells and highlight content