Add some real descriptions to the multiargument aggregate functions rather

than just showing the incomprehensible formulas.

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index c134e7169bfdfd4cc299fe6aaa9d6ec4e9b24950..96f9ce0a14df635bfe5b3e3dd3c4b30cb28617ba 100644 (file)
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1,4 +1,4 @@
-
+
 
  
   Functions and Operators
@@ -8102,17 +8102,7 @@ SELECT count(*) FROM sometable;
       
        double precision
       
-      sqrt((N *
-      sum(X*
-      class="parameter">Y) - sum(
-      class="parameter">X) * sum(
-      class="parameter">Y))^2 / ((
-      class="parameter">N * sum(
-      class="parameter">X^2) - sum(
-      class="parameter">X)^2) * (
-      class="parameter">N * sum(
-      class="parameter">Y^2) - sum(
-      class="parameter">Y)^2)))
+      correlation coefficient
      
 
      
@@ -8129,12 +8119,7 @@ SELECT count(*) FROM sometable;
       
        double precision
       
-      (sum(X*
-      class="parameter">Y) - sum(
-      class="parameter">X) * sum(
-      class="parameter">Y) / 
-      class="parameter">N) / 
-      class="parameter">N
+      population covariance
      
 
      
@@ -8151,12 +8136,7 @@ SELECT count(*) FROM sometable;
       
        double precision
       
-      (sum(X*
-      class="parameter">Y) - sum(
-      class="parameter">X) * sum(
-      class="parameter">Y) / 
-      class="parameter">N) / (
-      class="parameter">N - 1)
+      sample covariance
      
 
      
@@ -8169,8 +8149,8 @@ SELECT count(*) FROM sometable;
       
        double precision
       
-      sum(X) /
-      N
+      average of the independent variable
+      (sum(X)/N)
      
 
      
@@ -8183,8 +8163,8 @@ SELECT count(*) FROM sometable;
       
        double precision
       
-      sum(Y) /
-      N
+      average of the dependent variable
+      (sum(Y)/N)
      
 
      
@@ -8197,7 +8177,7 @@ SELECT count(*) FROM sometable;
       
        bigint
       
-      number of input rows in which both expressions are non-null
+      number of input rows in which both expressions are nonnull
      
 
      
@@ -8213,14 +8193,10 @@ SELECT count(*) FROM sometable;
       
        double precision
       
-      (sum(Y) *
-      sum(X^2) - sum(
-      class="parameter">X) * sum(
-      class="parameter">X*
-      class="parameter">Y)) / (
-      class="parameter">N * sum(
-      class="parameter">X^2) - sum(
-      class="parameter">X)^2)
+      y-intercept of the least-squares-fit linear equation
+      determined by the (
+      class="parameter">X, 
+      class="parameter">Y) pairs
      
 
      
@@ -8233,17 +8209,7 @@ SELECT count(*) FROM sometable;
       
        double precision
       
-      (N *
-      sum(X*
-      class="parameter">Y) - sum(
-      class="parameter">X) * sum(
-      class="parameter">Y))^2 / ((
-      class="parameter">N * sum(
-      class="parameter">X^2) - sum(
-      class="parameter">X)^2) * (
-      class="parameter">N * sum(
-      class="parameter">Y^2) - sum(
-      class="parameter">Y)^2))
+      square of the correlation coefficient
      
 
      
@@ -8259,14 +8225,9 @@ SELECT count(*) FROM sometable;
       
        double precision
       
-      (N *
-      sum(X*
-      class="parameter">Y) - sum(
-      class="parameter">X) * sum(
-      class="parameter">Y)) / (
-      class="parameter">N * sum(
-      class="parameter">X^2) - sum(
-      class="parameter">X)^2)
+      slope of the least-squares-fit linear equation determined
+      by the (X,
+      Y) pairs
      
 
      
@@ -8279,9 +8240,11 @@ SELECT count(*) FROM sometable;
       
        double precision
       
-      sum(X^2) -
-      sum(X)^2 / 
-      class="parameter">N
+      sum(
+      class="parameter">X^2) - sum(
+      class="parameter">X)^2/
+      class="parameter">N (sum of
+      squares of the independent variable)
      
 
      
@@ -8294,11 +8257,14 @@ SELECT count(*) FROM sometable;
       
        double precision
       
-      sum(X*
+      sum(
+      class="parameter">X*
       class="parameter">Y) - sum(
       class="parameter">X) * sum(
-      class="parameter">Y) / 
-      class="parameter">N
+      class="parameter">Y)/
+      class="parameter">N (sum of
+      products of independent times dependent
+      variable)
      
 
      
@@ -8311,9 +8277,11 @@ SELECT count(*) FROM sometable;
       
        double precision
       
-      sum(Y^2) -
-      sum(Y)^2 / 
-      class="parameter">N
+      sum(
+      class="parameter">Y^2) - sum(
+      class="parameter">Y)^2/
+      class="parameter">N (sum of
+      squares of the dependent variable)
      
 
      




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