Merge branch 'master' into cdb_querytables_quoted

Conflicts:
	test/extension/test.sh

scripts-available/CDB_ColumnNames.sql

@@ -3,11 +3,12 @@ CREATE OR REPLACE FUNCTION CDB_ColumnNames(REGCLASS)
 RETURNS SETOF information_schema.sql_identifier
 AS $$
 
-    SELECT column_name 
-      FROM information_schema.columns 
-      WHERE
-        table_name IN (SELECT CDB_UserTables())
-        AND table_name = '' || $1 || '';
+    SELECT c.column_name
+      FROM information_schema.columns c, pg_class _tn, pg_namespace _sn
+      WHERE table_name = _tn.relname
+        AND table_schema = _sn.nspname
+        AND _tn.oid = $1::oid
+        AND _sn.oid = _tn.relnamespace;
          
 $$ LANGUAGE SQL;
 

scripts-available/CDB_ColumnType.sql

@@ -3,12 +3,13 @@ CREATE OR REPLACE FUNCTION CDB_ColumnType(REGCLASS, TEXT)
 RETURNS information_schema.character_data
 AS $$
 
-    SELECT data_type 
-      FROM information_schema.columns 
-      WHERE
-        table_name IN (SELECT CDB_UserTables())
-        AND table_name = '' || $1 || ''
-        AND column_name = '' || quote_ident($2) || '';
+    SELECT c.data_type
+      FROM information_schema.columns c, pg_class _tn, pg_namespace _sn
+      WHERE table_name = _tn.relname
+        AND table_schema = _sn.nspname
+        AND column_name = $2
+        AND _tn.oid = $1::oid
+        AND _sn.oid = _tn.relnamespace;
          
 $$ LANGUAGE SQL;
 

scripts-available/CDB_Stats.sql

@@ -0,0 +1,47 @@
+--
+-- Calculate basic statistics of a given dataset
+--
+-- @param in_array A numeric array of numbers
+--
+-- Returns: statistical quantity chosen
+-- 
+-- References: http://www.itl.nist.gov/div898/handbook/eda/section3/eda35b.htm
+--
+
+-- Calculate kurtosis
+CREATE OR REPLACE FUNCTION CDB_Kurtosis ( in_array NUMERIC[] ) RETURNS NUMERIC as $$
+DECLARE
+    a numeric;
+    c numeric;
+    s numeric;
+    k numeric;
+BEGIN
+    SELECT AVG(e), COUNT(e)::numeric, stddev(e) INTO a, c, s FROM ( SELECT unnest(in_array) e ) x;
+
+    EXECUTE 'SELECT sum(power($1 - e, 4)) / ( $2 * power($3, 4)) - 3
+             FROM (SELECT unnest($4) e ) x'
+    INTO k
+    USING a, c, s, in_array;
+
+    RETURN k;
+END;
+$$ language plpgsql IMMUTABLE;
+
+-- Calculate skewness
+CREATE OR REPLACE FUNCTION CDB_Skewness ( in_array NUMERIC[] ) RETURNS NUMERIC as $$
+DECLARE
+    a numeric;
+    c numeric;
+    s numeric;
+    sk numeric;
+BEGIN
+    SELECT AVG(e), COUNT(e)::numeric, stddev(e) INTO a, c, s FROM ( SELECT unnest(in_array) e ) x;
+
+    EXECUTE 'SELECT sum(power($1 - e, 3)) / ( $2 * power($3, 3))
+             FROM (SELECT unnest($4) e ) x'
+    INTO sk
+    USING a, c, s, in_array;
+
+    RETURN sk;
+END;
+$$ language plpgsql IMMUTABLE;