Lookup only When Creating Records
To allow searching only in the New record form and not the Edit record form, place after the SQL statement this option !NEW :

$lens->searchLookupLens = "name^select name from customer where name like '{#}%' ^!NEW";

Lookup Switches from New to Edit
Suppose you don't want to populate the New record form when you find a match, but switch to editing the selected record, set the 2nd field of the select statement to the primary key of the record to be edited (custid in this example), and place after the SQL statement this option !NEWEDIT :

$lens->searchLookupLens = "name^select name,custid from customer where name like '{#}%' ^!NEWEDIT";

Require a Minimum Number of Characters to be Searched
Now you might require the user enter at least 3 characters in the search field before you allow them to click on the Search button. To do so add a '>3' to the property:

$lens->searchLookupLens =
  "name^select name,name,id,address from customer where name like '{#}%' ^name^custid^address^>3";

Advanced Lookups (combining lookupLens with searchLookupLens)

The above examples assume that you are modifying the name directly. But suppose we store cust_id, a foreign key to the CUSTOMER table in the COMPLAINT table and not the actual customer name. We don't want the user to search for the cust_id, which is an integer and internal to the database. We want to search by name instead. We need to do a little more work here...

First we need a mapping between the CUSTOMER and COMPLAINT tables. This is done using the normal lookupLens. We don't want to pull the whole CUSTOMER table over, so we use a hot update that only works in NEW and EDIT mode. The -VIEW means not when viewing records.

$lens->lookupLens = 'cust_id^#select cust_id,name from customer where cust_id = {cust_id}^-VIEW';

Then have a searchLookupLens for the cust_id field, such as the following:

$lens->searchLookupLens = "cust_id^select name||': '||address,name,cust_id from customer where name like '{#}%' ";

There must be 3 columns in the select statement:

1. the column to show to the end-user to select from a popup menu (in this example, the name followed by the address),
2. the value to display in the text field after selection, and
3. the actual value to store in the record (in the COMPLAINTS table, cust_id field).