From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 9 Jul 2007 16:14:06 +0000 (+0000)
Subject: Fix stddev_pop(numeric) and var_pop(numeric), which were incorrectly producing
X-Git-Url: http://waps.l3s.uni-hannover.de/gitweb/?a=commitdiff_plain;h=b4a92ea6ee339098df7e3da440d11371450b21f1;p=users%2Fbernd%2Fpostgres.git

Fix stddev_pop(numeric) and var_pop(numeric), which were incorrectly producing
the same outputs as stddev_samp() and var_samp() respectively.
---

diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c
index 1593a0cc36..a1abad9b61 100644
--- a/src/backend/utils/adt/numeric.c
+++ b/src/backend/utils/adt/numeric.c
@@ -2274,7 +2274,10 @@ numeric_stddev_internal(ArrayType *transarray,
 	}
 	else
 	{
-		mul_var(&vN, &vNminus1, &vNminus1, 0);	/* N * (N - 1) */
+		if (sample)
+			mul_var(&vN, &vNminus1, &vNminus1, 0);	/* N * (N - 1) */
+		else
+			mul_var(&vN, &vN, &vNminus1, 0);		/* N * N */
 		rscale = select_div_scale(&vsumX2, &vNminus1);
 		div_var(&vsumX2, &vNminus1, &vsumX, rscale, true);		/* variance */
 		if (!variance)
diff --git a/src/test/regress/expected/aggregates.out b/src/test/regress/expected/aggregates.out
index 34b720f0f4..74635479e4 100644
--- a/src/test/regress/expected/aggregates.out
+++ b/src/test/regress/expected/aggregates.out
@@ -102,7 +102,7 @@ SELECT var_samp(b) FROM aggtest;
 SELECT stddev_pop(b::numeric) FROM aggtest;
     stddev_pop    
 ------------------
- 151.389361431288
+ 131.107032862199
 (1 row)
 
 SELECT stddev_samp(b::numeric) FROM aggtest;
@@ -114,7 +114,7 @@ SELECT stddev_samp(b::numeric) FROM aggtest;
 SELECT var_pop(b::numeric) FROM aggtest;
       var_pop       
 --------------------
- 22918.738754573025
+ 17189.054065929769
 (1 row)
 
 SELECT var_samp(b::numeric) FROM aggtest;