<?xml version="1.0" encoding="UTF-8"?><rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>The Prepshotz blog</title><link>https://prepshotz.com/blog/</link><atom:link href="https://prepshotz.com/blog/rss.xml" rel="self" type="application/rss+xml"/><description>Coding errors explained, with code you can run in your browser.</description><language>en</language><lastBuildDate>Fri, 16 Oct 2026 00:00:00 GMT</lastBuildDate><item><title>Second highest salary in SQL: queries that handle ties</title><link>https://prepshotz.com/blog/second-highest-salary-sql/</link><guid>https://prepshotz.com/blog/second-highest-salary-sql/</guid><pubDate>Fri, 16 Oct 2026 00:00:00 GMT</pubDate><description>Four ways to find the second highest salary in SQL, the tie that breaks LIMIT 1 OFFSET 1, returning NULL when there is none, and the Nth highest.</description></item><item><title>Is DataLemur free? What you get without paying</title><link>https://prepshotz.com/blog/is-datalemur-free/</link><guid>https://prepshotz.com/blog/is-datalemur-free/</guid><pubDate>Wed, 14 Oct 2026 00:00:00 GMT</pubDate><description>Which DataLemur questions are free, what Premium costs and adds, and when the free tier is enough for SQL interview prep, checked 14 Oct 2026.</description></item><item><title>declared and not used in Go: why it fails and how to fix it</title><link>https://prepshotz.com/blog/go-declared-and-not-used/</link><guid>https://prepshotz.com/blog/go-declared-and-not-used/</guid><pubDate>Mon, 12 Oct 2026 00:00:00 GMT</pubDate><description>Why Go refuses to compile a local variable or an import you never use, the cases that cause it, and the fixes for each, with examples you can run.</description></item><item><title>TypeError: Cannot read properties of undefined, and the fix</title><link>https://prepshotz.com/blog/cannot-read-properties-of-undefined-javascript/</link><guid>https://prepshotz.com/blog/cannot-read-properties-of-undefined-javascript/</guid><pubDate>Fri, 09 Oct 2026 00:00:00 GMT</pubDate><description>Why JavaScript cannot read a property of undefined or null, the places that value comes from, and how to fix each one, with examples you can run.</description></item><item><title>Array index out of bounds in C: why there is no error</title><link>https://prepshotz.com/blog/array-index-out-of-bounds-in-c/</link><guid>https://prepshotz.com/blog/array-index-out-of-bounds-in-c/</guid><pubDate>Wed, 07 Oct 2026 00:00:00 GMT</pubDate><description>Why C reads and writes past the end of an array without an error or a segfault, what it breaks, and the compiler flags that name the exact line.</description></item><item><title>Column must appear in the GROUP BY clause: the PostgreSQL fix</title><link>https://prepshotz.com/blog/column-must-appear-in-the-group-by-clause/</link><guid>https://prepshotz.com/blog/column-must-appear-in-the-group-by-clause/</guid><pubDate>Wed, 07 Oct 2026 00:00:00 GMT</pubDate><description>What PostgreSQL means by a column that must appear in the GROUP BY clause, four fixes you can run, and how to get the whole top row in each group.</description></item><item><title>IndexError: list index out of range in Python, and how to fix it</title><link>https://prepshotz.com/blog/indexerror-list-index-out-of-range-python/</link><guid>https://prepshotz.com/blog/indexerror-list-index-out-of-range-python/</guid><pubDate>Wed, 07 Oct 2026 00:00:00 GMT</pubDate><description>What Python's list index out of range error means, why a for loop causes it, the tuple and pop versions, and the fix for each, with examples you can run.</description></item><item><title>TypeError: 'NoneType' object is not subscriptable, and the fix</title><link>https://prepshotz.com/blog/nonetype-object-is-not-subscriptable/</link><guid>https://prepshotz.com/blog/nonetype-object-is-not-subscriptable/</guid><pubDate>Wed, 07 Oct 2026 00:00:00 GMT</pubDate><description>Why Python says None is not subscriptable, where the None comes from, including sort(), recursion and pandas inplace=True, and how to fix each one.</description></item></channel></rss>