Drag and drop
Most things in Q can be sorted by clicking on them and moving them around. If moving rows or columns in a table around in this manner, carefully look at the tooltips (the small descriptions that appear as you move the mouse around), as you may inadvertently merge categories rather than moving them around.
Tables can be sorted by right-clicking on row or column headings and selecting Sort by. The options available are determined by where you right-click. For example, if you right-click on a column heading, you will get options for sorting the table based on the values in the column. When sorting a table in this way, everything will sort, including Other, None and NET categories - see QScripts and Rules for ways to address this.
QScripts and Rules
Many different Rules and QScripts address sorting, such as Sort/Reorder Rows or Columns - Sort Rows (Automatically Updates When Data Changes) and Sort/Reorder Rows or Columns - Sort Categories from Highest to Lowest (Does Not Update When Data Changes).