Select large number of rows

[#1]

Hello,
I am looking for tips to help me select a large number of lines easily. Indeed, I work with large databases and when I want to select 15000 lines for example, I click on the first line and I scroll down to 15000. Then when I want to select the following 15000 lines I click on line 15001 and I scroll down to 30001 with my computer mouse
I tried with keyboard keys but it's also very long ...
Do you know of a faster way to select a large number of rows?
Thank you

[#2]

JMP does offer you Select Where option. Couple of questions:

1. Is the selection always done for 15000 rows starting from top? 
2. What is done with the 15000 selected rows afterwards

Edit:

Without not knowledge of what the data looks like or will be used like I would most likely create new column with formula like:

Floor((Row()-1)/15000)

From this new column you can use right click and Select Matching cells (and press F6 to get to previous value and F7 to next value).

[#3]

Here is a real easy way to do what you are talking about.

You can use a Data Filter to select the rows you want.  Just create a new column, which has the row number as it's value.   I typically call the new column "TheRow".  Use

Row()

 as the formula for the column

Now just go to 

     Rows=>Data Filter

and choose column "TheRow" as what to filter on. 

You can either enter in absolute values as seen above, or interactively move the lower and upper boundaries to the values you want