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
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
CHAR vs VARCHAR Padding?!
CHAR PADS with spaces! VARCHAR doesn't. LENGTH() returns different values for same string in CHAR vs VARCHAR. This padding will break comparisons!
#sql #sqltricks #char #varchar #padding #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #stringtypes #advancedsql
Conditional Aggregation with CASE?!
CASE inside SUM creates conditional aggregation! You can sum only certain rows based on conditions. This conditional math will transform your data!
#sql #sqltricks #case #sum #conditionalaggregation #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #aggregation #advancedsql
Date Arithmetic with Leap Year?!
Leap years BREAK date math! February 28 + 1 day = February 29 in leap years, March 1 in non-leap years. This edge case will cause bugs!
#sql #sqltricks #datearithmetic #leapyear #dateadd #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #datefunctions #advancedsql
LAG - LEAD Default Value Trap?!
LAG and LEAD have DEFAULT values! When there's no previous/next row, they return the default. This hidden parameter will surprise you!
#sql #sqltricks #lag #lead #defaultvalue #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #windowfunctions #advancedsql
NULLIF and COALESCE Chain?!
NULLIF and COALESCE can be CHAINED! NULLIF converts to NULL, COALESCE converts from NULL. This transformation chain will surprise you!
#sql #sqltricks #nullif #coalesce #functionchaining #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #nullhandling #advancedsql
Window PARTITION BY Changes Results?!
PARTITION BY creates separate windows! Each partition has its own running sum. This partitioning will change your aggregation results!
#sql #sqltricks #partitionby #windowfunctions #runningsum #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #advancedsql
PrecisionSQL