Step-by-step tutorials on Excel, Python, databases, and developer tools
132 articles
Your SUMIFS formula looks right, but the total is suspiciously low. The culprit is almost always invisible trailing spaces in your criteria column — here's how to find them and fix them fast.
VLOOKUP can only search the leftmost column of your table array — anything else gives you #N/A. Here's why it happens and three practical ways to fix it without rearranging your entire spreadsheet.
Your Pandas pivot_table looks right but returns NaN in half the cells. The culprit is almost always an aggfunc receiving an empty group — here's how to diagnose and fix it cleanly.
Your SUMIFS formula looks correct, but it returns zero — and the culprit is a #N/A, #VALUE!, or #REF! lurking in your criteria range. Here's exactly why it breaks and three reliable ways to fix it.
Your INDEX MATCH formula looks correct, but it keeps returning #N/A whenever the lookup value starts with a zero. The culprit is almost always a data-type mismatch between text and numbers — here's exactly how to diagnose and fix it.
SUMIFS returning a suspiciously low or incorrect total? If your sum range has merged cells, Excel is only reading the top-left cell of each merge — silently ignoring the rest. Here's how to find and fix it.
Your partial index exists, VACUUM has run, and EXPLAIN still shows a sequential scan. The culprit is almost always a type mismatch between your query's WHERE clause and the index predicate. Here's how to diagnose and fix it fast.
Your SUMIFS formula looks correct but keeps returning zero. The culprit is often numbers stored as text in your sum range — a silent data type mismatch Excel won't warn you about. Here's how to find and fix it fast.
Your SUMPRODUCT formula looks right, but it keeps returning zero — and the only thing unusual about your sheet is a handful of merged cells in the criteria column. Here's exactly why that happens and how to fix it.
Your SUMIFS formula looks right, but it returns zero the moment you swap a cell reference for an array constant like {"North","South"}. Here's exactly why that happens and four reliable ways to fix it.
Your SUMIFS formula looks correct, but it keeps returning zero whenever you use date criteria. The culprit is almost always text-formatted date cells that Excel refuses to compare as real dates. Here's how to diagnose and fix it fast.
Your SUMIFS formula looks correct, but it's pulling in rows you never intended — rows where the criteria cell is blank or holds a number stored as text. Here's exactly why mixed data types trip up SUMIFS and how to fix it.