Display output even if the parameter, assign, is used
0 or 1 (exclusive)
Not set. Output is not displayed if assign is used
display_on_assign="1"
Output
The ratio of hits over joins. For example, 1:1.
If the assign parameter is used, output is put in the variable named by assign_prefix and assign and not displayed. If assign and display_on_assign are both used, output is put in a variable and displayed.