feat(cubesql): Enable COVAR aggr functions push down

Author: MazterQyou

packages/cubejs-schema-compiler/src/adapter/BaseQuery.js

@@ -2433,6 +2433,8 @@ class BaseQuery {
         STDDEV_SAMP: 'STDDEV_SAMP({{ args_concat }})',
         VAR_POP: 'VAR_POP({{ args_concat }})',
         VAR_SAMP: 'VAR_SAMP({{ args_concat }})',
+        COVAR_POP: 'COVAR_POP({{ args_concat }})',
+        COVAR_SAMP: 'COVAR_SAMP({{ args_concat }})',
 
         COALESCE: 'COALESCE({{ args_concat }})',
         CONCAT: 'CONCAT({{ args_concat }})',

packages/cubejs-schema-compiler/src/adapter/RedshiftQuery.js

@@ -11,4 +11,12 @@ export class RedshiftQuery extends PostgresQuery {
   nowTimestampSql() {
     return 'GETDATE()';
   }
+
+  sqlTemplates() {
+    return {
+      ...super.sqlTemplates(),
+      COVAR_POP: undefined,
+      COVAR_SAMP: undefined,
+    };
+  }
 }