#advancedsql — Public Fediverse posts
Live and recent posts from across the Fediverse tagged #advancedsql, aggregated by home.social.
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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DATE_FORMAT with Edge Cases?!
DATE_FORMAT has HUNDREDS of format codes! %j is day of year, %W is weekday name. This formatting language will confuse you!
#sql #sqltricks #dateformat #formatcodes #dateformatting #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #datefunctions #advancedsql
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DATE_FORMAT with Edge Cases?!
DATE_FORMAT has HUNDREDS of format codes! %j is day of year, %W is weekday name. This formatting language will confuse you!
#sql #sqltricks #dateformat #formatcodes #dateformatting #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #datefunctions #advancedsql
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JSON Path Expressions Extract Data?!
JSON_EXTRACT uses PATH syntax! The $ symbol means root, . means property access. This JSON path language will confuse you!
#sql #sqltricks #jsonextract #jsonpath #jsonunquote #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #jsonfunctions #advancedsql
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JSON Path Expressions Extract Data?!
JSON_EXTRACT uses PATH syntax! The $ symbol means root, . means property access. This JSON path language will confuse you!
#sql #sqltricks #jsonextract #jsonpath #jsonunquote #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #jsonfunctions #advancedsql
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String Collation Changes Comparison?!
Collation CHANGES string comparison! Case-insensitive collation makes 'A' = 'a'. This hidden setting will break your WHERE clauses!
#sql #sqltricks #collation #stringcomparison #casesensitivity #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #stringfunctions #advancedsql
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String Collation Changes Comparison?!
Collation CHANGES string comparison! Case-insensitive collation makes 'A' = 'a'. This hidden setting will break your WHERE clauses!
#sql #sqltricks #collation #stringcomparison #casesensitivity #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #stringfunctions #advancedsql
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Self-Join with Aliases Trap?!
Self-joins need DIFFERENT aliases! Same table, different names. The join condition creates relationships within the same table. This will confuse you!
#sql #sqltricks #selfjoin #aliases #tablealiases #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #joins #advancedsql
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Self-Join with Aliases Trap?!
Self-joins need DIFFERENT aliases! Same table, different names. The join condition creates relationships within the same table. This will confuse you!
#sql #sqltricks #selfjoin #aliases #tablealiases #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #joins #advancedsql
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NTH_VALUE Gets Specific Position?!
NTH_VALUE extracts the Nth value from window! It's like array indexing for window functions. This positional access will surprise you!
#sql #sqltricks #nthvalue #windowfunctions #positionalaccess #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #advancedsql
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NTH_VALUE Gets Specific Position?!
NTH_VALUE extracts the Nth value from window! It's like array indexing for window functions. This positional access will surprise you!
#sql #sqltricks #nthvalue #windowfunctions #positionalaccess #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #advancedsql
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CTE Referenced Multiple Times?!
CTEs can be referenced MULTIPLE times! The same CTE appears in different parts of the query. This reusability will simplify complex queries!
#sql #sqltricks #cte #withclause #multiplereferences #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #commontableexpressions #advancedsql
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CTE Referenced Multiple Times?!
CTEs can be referenced MULTIPLE times! The same CTE appears in different parts of the query. This reusability will simplify complex queries!
#sql #sqltricks #cte #withclause #multiplereferences #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #commontableexpressions #advancedsql
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EXISTS vs IN with NULLs?!
EXISTS and IN handle NULLs DIFFERENTLY! IN returns NULL when NULL is in the list, EXISTS doesn't. This NULL behavior will cause bugs!
#sql #sqltricks #exists #in #nullhandling #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #subqueries #advancedsql
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EXISTS vs IN with NULLs?!
EXISTS and IN handle NULLs DIFFERENTLY! IN returns NULL when NULL is in the list, EXISTS doesn't. This NULL behavior will cause bugs!
#sql #sqltricks #exists #in #nullhandling #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #subqueries #advancedsql
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Correlated Subquery in SELECT?!
Subqueries in SELECT execute for EVERY row! This correlated subquery runs once per row, creating a performance nightmare. This is why queries are slow!
#sql #sqltricks #correlatedsubquery #selectclause #performance #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #subqueries #advancedsql
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Correlated Subquery in SELECT?!
Subqueries in SELECT execute for EVERY row! This correlated subquery runs once per row, creating a performance nightmare. This is why queries are slow!
#sql #sqltricks #correlatedsubquery #selectclause #performance #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #subqueries #advancedsql
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Recursive CTE Termination Condition?!
Recursive CTEs can loop FOREVER! The termination condition is CRITICAL. One wrong condition and your query hangs. This is how infinite loops happen in SQL!
#sql #sqltricks #recursivecte #withrecursive #termination #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #cterecursion #advancedsql
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Recursive CTE Termination Condition?!
Recursive CTEs can loop FOREVER! The termination condition is CRITICAL. One wrong condition and your query hangs. This is how infinite loops happen in SQL!
#sql #sqltricks #recursivecte #withrecursive #termination #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #cterecursion #advancedsql
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INTERSECT vs INNER JOIN?!
INTERSECT and INNER JOIN are DIFFERENT! INTERSECT removes duplicates, JOIN doesn't. Same data, different results. This will break your logic!
#sql #sqltricks #intersect #innerjoin #setoperations #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #joins #advancedsql
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INTERSECT vs INNER JOIN?!
INTERSECT and INNER JOIN are DIFFERENT! INTERSECT removes duplicates, JOIN doesn't. Same data, different results. This will break your logic!
#sql #sqltricks #intersect #innerjoin #setoperations #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #joins #advancedsql
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Window ROWS vs RANGE Frame Difference?!
ROWS and RANGE frames are COMPLETELY different! ROWS counts physical rows, RANGE groups by value. Same query, DIFFERENT results. This will confuse you!
#sql #sqltricks #windowfunctions #rowsvsrange #framespecification #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #advancedsql #database
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Window ROWS vs RANGE Frame Difference?!
ROWS and RANGE frames are COMPLETELY different! ROWS counts physical rows, RANGE groups by value. Same query, DIFFERENT results. This will confuse you!
#sql #sqltricks #windowfunctions #rowsvsrange #framespecification #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #advancedsql #database
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CASE Expression with NULL Comparison?!
CASE expressions have NULL traps! NULL = NULL is UNKNOWN, not TRUE. The CASE logic handles this differently than you expect!
#sql #sqltricks #case #nullcomparison #threevaluedlogic #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #conditionallogic #advancedsql
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CASE Expression with NULL Comparison?!
CASE expressions have NULL traps! NULL = NULL is UNKNOWN, not TRUE. The CASE logic handles this differently than you expect!
#sql #sqltricks #case #nullcomparison #threevaluedlogic #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #conditionallogic #advancedsql
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UNION ALL Preserves Duplicates?!
UNION ALL keeps ALL rows! UNION removes duplicates. This one keyword difference changes the entire result set. This will break your data!
#sql #sqltricks #union #unionall #duplicates #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #setoperations #advancedsql
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UNION ALL Preserves Duplicates?!
UNION ALL keeps ALL rows! UNION removes duplicates. This one keyword difference changes the entire result set. This will break your data!
#sql #sqltricks #union #unionall #duplicates #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #setoperations #advancedsql
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RANK vs DENSE_RANK vs ROW_NUMBER?!
Three ranking functions, THREE different behaviors! RANK skips numbers, DENSE_RANK doesn't, ROW_NUMBER always increments. This difference BREAKS logic!
#sql #sqltricks #rank #denserank #rownumber #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #rankingfunctions #advancedsql
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RANK vs DENSE_RANK vs ROW_NUMBER?!
Three ranking functions, THREE different behaviors! RANK skips numbers, DENSE_RANK doesn't, ROW_NUMBER always increments. This difference BREAKS logic!
#sql #sqltricks #rank #denserank #rownumber #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #rankingfunctions #advancedsql
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Correlated Subquery in WHERE?!
Correlated subqueries in WHERE execute for EVERY row! They reference outer query columns, creating a performance nightmare. This is why queries are slow!
#sql #sqltricks #correlatedsubquery #whereclause #performance #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #subqueries #advancedsql
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Correlated Subquery in WHERE?!
Correlated subqueries in WHERE execute for EVERY row! They reference outer query columns, creating a performance nightmare. This is why queries are slow!
#sql #sqltricks #correlatedsubquery #whereclause #performance #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #subqueries #advancedsql
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Window Frame UNBOUNDED?!
UNBOUNDED PRECEDING means ALL previous rows! UNBOUNDED FOLLOWING means ALL future rows. This creates running totals across the entire window!
#sql #sqltricks #unbounded #preceding #following #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #windowframes #advancedsql
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Window Frame UNBOUNDED?!
UNBOUNDED PRECEDING means ALL previous rows! UNBOUNDED FOLLOWING means ALL future rows. This creates running totals across the entire window!
#sql #sqltricks #unbounded #preceding #following #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #windowframes #advancedsql
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GROUPING SETS / ROLLUP / CUBE?!
ROLLUP creates MULTIPLE grouping levels! It generates subtotals and grand totals automatically. This one query returns MANY result sets!
#sql #sqltricks #rollup #cube #groupingsets #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #aggregation #advancedsql
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GROUPING SETS / ROLLUP / CUBE?!
ROLLUP creates MULTIPLE grouping levels! It generates subtotals and grand totals automatically. This one query returns MANY result sets!
#sql #sqltricks #rollup #cube #groupingsets #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #aggregation #advancedsql
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EXCEPT vs NOT EXISTS?!
EXCEPT removes rows from first set! It's like subtraction for result sets. NOT EXISTS does similar but differently. This set operation will confuse you!
#sql #sqltricks #except #notexists #setdifference #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #setoperations #advancedsql
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EXCEPT vs NOT EXISTS?!
EXCEPT removes rows from first set! It's like subtraction for result sets. NOT EXISTS does similar but differently. This set operation will confuse you!
#sql #sqltricks #except #notexists #setdifference #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #setoperations #advancedsql
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COALESCE vs NULLIF Trap?!
NULLIF converts values to NULL! COALESCE converts NULL to values. Together they create a transformation chain that will surprise you!
#sql #sqltricks #coalesce #nullif #nullhandling #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #nullfunctions #advancedsql
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COALESCE vs NULLIF Trap?!
NULLIF converts values to NULL! COALESCE converts NULL to values. Together they create a transformation chain that will surprise you!
#sql #sqltricks #coalesce #nullif #nullhandling #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #nullfunctions #advancedsql
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CASE Expression with NULL Comparison?!
CASE expressions have NULL traps! NULL = NULL is UNKNOWN, not TRUE. The CASE logic handles this differently than you expect!
#sql #sqltricks #case #nullcomparison #threevaluedlogic #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #conditionallogic #advancedsql
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CASE Expression with NULL Comparison?!
CASE expressions have NULL traps! NULL = NULL is UNKNOWN, not TRUE. The CASE logic handles this differently than you expect!
#sql #sqltricks #case #nullcomparison #threevaluedlogic #sqlweird #sqlquiz #codingchallenge #sqlshorts #sqlwtf #conditionallogic #advancedsql