2026-03-12 20:23:15

Kevin_Meade/showhistograms.sql

@@ -0,0 +1,29 @@
+--
+-- shows the histogram for a specific column
+-- very usefull for showing when statistics might not help
+--
+-- parameter 1 = owner
+-- parameter 2 = table_name
+-- parameter 3 = column_name
+--
+-- usage is: @SHOWHISTOGRAM <owner> <table_name> <column_name>
+--
+
+COLUMN   endpoint_actual_value noprint
+COLUMN   actual_value ON FORMAT   a30
+col column format a30
+
+
+select b.*
+      ,round(ratio_to_report(cardinality) over(partition by owner,table_name,column_name)*100) pct
+      ,endpoint_actual_value actual_value
+from (
+select a.*
+      ,ENDPOINT_NUMBER-nvl(lag(ENDPOINT_NUMBER) over(partition by owner,table_name,column_name order by endpoint_number),0) cardinality
+from dba_histograms a
+where owner = upper('&&1')
+and table_name = upper('&&2')
+and column_name = upper('&&3')
+) b
+order by owner,table_name,column_name,ENDPOINT_NUMBER
+/