Subquery Returns Multiple Rows In Comparison?!
Using subquery that returns multiple rows in = comparison crashes! SQL doesn't know which row to use. This breaks subqueries! Watch!
#sql #sqltricks #database #sqltutorial #subqueries #multiplerows #sqlquiz #codingchallenge #sqlshorts #sqlbugs #subqueryerrors #sqlwtf
0.1 + 0.2 In SQL = 0.30000000000000004?!
SQL floating point precision is broken! Adding 0.1 + 0.2 creates a number with precision errors. This breaks financial calculations! Watch!
#sql #sqltricks #database #sqltutorial #floatingpoint #precision #sqlquiz #codingchallenge #sqlshorts #sqlbugs #numericprecision #sqlwtf
HAVING Filters After GROUP BY?!
HAVING filters GROUPS, WHERE filters ROWS! HAVING runs after aggregation, WHERE runs before. This order matters and will break your logic!
#sql #sqltricks #having #where #groupby #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #aggregation #advancedsql
Window ORDER BY NULLS FIRST - LAST?!
NULLS FIRST and NULLS LAST change window function results! The order of NULLs matters in window functions. This subtle difference will cause bugs!
#sql #sqltricks #windowfunctions #nullsfirst #nullslast #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #nullhandling #advancedsql
Decimal Precision Rounds Numbers?!
DECIMAL precision ROUNDS values! Cast 1.999 to DECIMAL(5,2) and it becomes 2.00. This silent rounding will cause calculation errors!
#sql #sqltricks #decimal #precision #rounding #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #datatypes #advancedsql
COUNT(*) vs COUNT(column) Are DIFFERENT?!
COUNT(*) and COUNT(column) behave completely differently with NULLs! One counts NULLs, one doesn't. This breaks aggregate logic! Watch!
#sql #sqltricks #database #sqltutorial #count #aggregate #sqlquiz #codingchallenge #sqlshorts #sqlbugs #nullhandling #sqlwtf
JOIN With NULL Keys Returns ZERO Rows?!
JOINing tables with NULL keys returns ZERO rows! NULL = NULL in JOIN is FALSE. This breaks all join logic! Watch!
#sql #sqltricks #database #sqltutorial #join #nullkeys #sqlquiz #codingchallenge #sqlshorts #sqlbugs #joins #sqlwtf
ROW_NUMBER() OVER (ORDER BY NULL) Does WHAT?!
ROW_NUMBER with ORDER BY NULL creates non-deterministic ordering! All rows get random numbers. This breaks window functions! Watch!
#sql #sqltricks #database #sqltutorial #rownumber #windowfunctions #sqlquiz #codingchallenge #sqlshorts #sqlbugs #ordering #sqlwtf
LEN('') vs LEN(NULL) vs LEN(' ') Are DIFFERENT?!
LEN of empty string, NULL, and space are all different! Empty = 0, NULL = NULL, Space = 1. This breaks string length logic! Watch!
#sql #sqltricks #database #sqltutorial #len #stringlength #sqlquiz #codingchallenge #sqlshorts #sqlbugs #stringfunctions #sqlwtf
TRIM with Different Characters?!
TRIM can remove ANY character! Not just spaces. LEADING, TRAILING, or BOTH. This flexible trimming will clean your data in unexpected ways!
#sql #sqltricks #trim #leading #trailing #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #stringfunctions #advancedsql
PrecisionSQL