You can select multiple rows in the Search > Campaigns, Search > Label Classifications, and Optimization > Constraints views in the following ways:
Shift+Click: To select multiple, consecutive rows, click the first one and press Shift while you click the last one.
Ctrl+Click: To select multiple, non-consecutive rows, click the first one and then press Ctrl while you click each additional row.
Global check box ( “Check box”) in the upper-left column heading:
To select all rows on the current page — which may include some or all rows available with the applied filters, based on whether you’re viewing 25 rows, 50 rows, 100 rows, 200 rows, or Continuous Scroll — select the global check box.
When you select all rows on the page, you can de-select individual rows.
To select all rows available with the applied filters, select the global check box, and then click Select all N records?, where N is the number of available records.
When you select all rows available, you can’t de-select individual rows.