IT Engineering Skills: Master Excel — Merge Data From Two Sources!

In the first video of my IT Engineering Skills series, we look at practical Excel data manipulation: joining and reconciling data across multiple exports using VLOOKUP and IFERROR.

Whether you are correlating phone MAC addresses against switch port exports, reconciling DID inventories between carrier billing CSVs and CUCM/Zoom Phone, or auditing user license assignments across Active Directory and your UCaaS tenant, knowing how to cleanly join two spreadsheets is an indispensable day-to-day engineering skill.

Core Formula Reference

1. Joining Data with VLOOKUP

=VLOOKUP(lookup_value, table_array, col_index_num, FALSE)

• lookup_value: The unique key in your current row (such as an extension, E.164 DID, MAC address, or email address).
• table_array: The target range in your second sheet or workbook (always lock the range with absolute references like $A$2:$D$500 so it doesn’t shift when you fill down).
• col_index_num: The column number within table_array containing the value you want to return (1 is the leftmost key column, 2 is the second column, etc.).
• FALSE: Forces an exact match (critical when matching extensions, phone numbers, or hardware IDs).

2. Wrapping with IFERROR for Clean Audits

When reconciling two IT systems, missing records return #N/A. Wrapping your lookup in IFERROR lets you label missing records cleanly for filtering:

=IFERROR(VLOOKUP(A2, Sheet2!$A$2:$C$1000, 2, FALSE), "Not Found in Carrier Inventory")