Add statistical type aggregate functions, including autocorrelation, skewness, and linear regression

integration-test/src/main/java/org/apache/iotdb/itbase/constant/BuiltinAggregationFunctionEnum.java

@@ -44,7 +44,14 @@ public enum BuiltinAggregationFunctionEnum {
   AVG("avg"),
   SUM("sum"),
   MAX_BY("max_by"),
-  MIN_BY("min_by");
+  MIN_BY("min_by"),
+  CORR("corr"),
+  COVAR_POP("covar_pop"),
+  COVAR_SAMP("covar_samp"),
+  REGR_SLOPE("regr_slope"),
+  REGR_INTERCEPT("regr_intercept"),
+  SKEWNESS("skewness"),
+  KURTOSIS("kurtosis");
 
   private final String functionName;
 

integration-test/src/main/java/org/apache/iotdb/itbase/constant/TestConstant.java

@@ -145,6 +145,34 @@ public static String varSamp(String path) {
     return String.format("var_samp(%s)", path);
   }
 
+  public static String corr(String path) {
+    return String.format("corr(%s)", path);
+  }
+
+  public static String covarPop(String path) {
+    return String.format("covar_pop(%s)", path);
+  }
+
+  public static String covarSamp(String path) {
+    return String.format("covar_samp(%s)", path);
+  }
+
+  public static String regrSlope(String path) {
+    return String.format("regr_slope(%s)", path);
+  }
+
+  public static String regrIntercept(String path) {
+    return String.format("regr_intercept(%s)", path);
+  }
+
+  public static String kurtosis(String path) {
+    return String.format("kurtosis(%s)", path);
+  }
+
+  public static String skewness(String path) {
+    return String.format("skewness(%s)", path);
+  }
+
   public static String countUDAF(String path) {
     return String.format("count_udaf(%s)", path);
   }