From 1bf0b42abd74a723328ddaced8b4cec4f15a8862 Mon Sep 17 00:00:00 2001
From: Felix Mueller <5407006+enqueue@users.noreply.github.com>
Date: Fri, 6 Sep 2019 13:26:36 +0200
Subject: [PATCH] fix is-empty comparison (#32)

---
 src/metabase/driver/clickhouse.clj       | 19 ++++++++++---------
 test/metabase/driver/clickhouse_test.clj | 13 +++++++++++++
 2 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/src/metabase/driver/clickhouse.clj b/src/metabase/driver/clickhouse.clj
index a826e35..4379de3 100644
--- a/src/metabase/driver/clickhouse.clj
+++ b/src/metabase/driver/clickhouse.clj
@@ -189,9 +189,11 @@
 ;; the filter criterion reads "is empty"
 ;; also see desugar.clj
 (defmethod sql.qp/->honeysql [:clickhouse :=] [driver [_ field value]]
-  (let [base-type (:base_type (last value)) value-value (:value value)]
-    (if (and (isa? base-type :type/Text)
-             (nil? value-value))
+  (let [[qual valuevalue fieldinfo] value]
+    (if (and
+         (isa? qual :value)
+         (isa? (:base_type fieldinfo) :type/Text)
+         (nil? valuevalue))
       [:or
        [:= (sql.qp/->honeysql driver field) (sql.qp/->honeysql driver value)]
        [:= (hsql/call :empty (sql.qp/->honeysql driver field)) 1]]
@@ -200,15 +202,16 @@
 ;; the filter criterion reads "not empty"
 ;; also see desugar.clj
 (defmethod sql.qp/->honeysql [:clickhouse :!=] [driver [_ field value]]
-  (let [base-type (:base_type (last value)) value-value (:value value)]
-    (if (and (isa? base-type :type/Text)
-             (nil? value-value))
+  (let [[qual valuevalue fieldinfo] value]
+    (if (and
+         (isa? qual :value)
+         (isa? (:base_type fieldinfo) :type/Text)
+         (nil? valuevalue))
       [:and
        [:!= (sql.qp/->honeysql driver field) (sql.qp/->honeysql driver value)]
        [:= (hsql/call :notEmpty (sql.qp/->honeysql driver field)) 1]]
       ((get-method sql.qp/->honeysql [:sql :!=]) driver [_ field value]))))
 
-
 ;; I do not know why the tests expect nil counts for empty results
 ;; but that's how it is :-)
 ;; metabase.query-processor-test.count-where-test
@@ -317,8 +320,6 @@
 (defmethod driver/current-db-time :clickhouse [& args]
   (apply driver.common/current-db-time args))
 
-
-
 (defmethod driver/display-name :clickhouse [_] "ClickHouse")
 
 (defmethod driver/supports? [:clickhouse :foreign-keys] [_ _] false)
diff --git a/test/metabase/driver/clickhouse_test.clj b/test/metabase/driver/clickhouse_test.clj
index 9e92618..0a127c2 100644
--- a/test/metabase/driver/clickhouse_test.clj
+++ b/test/metabase/driver/clickhouse_test.clj
@@ -62,12 +62,25 @@
   (-> (data/dataset (tx/dataset-definition "metabase_tests_nullable_strings"
                       ["test-data-nullable-strings"
                        [{:field-name "mystring", :base-type :type/Text}]
+
                        [["foo"], ["bar"], ["   "], [""], [nil]]])
                     (data/run-mbql-query test-data-nullable-strings
                                          {:filter [:not-null $mystring]
                                           :aggregation [:count]}))
       qp.test/first-row last))
 
+(datasets/expect-with-driver :clickhouse
+  1
+  (-> (data/dataset (tx/dataset-definition "metabase_tests_nullable_strings"
+                      ["test-data-nullable-strings"
+                       [{:field-name "mystring", :base-type :type/Text}]
+
+                       [["foo"], ["bar"], ["   "], [""], [nil]]])
+                    (data/run-mbql-query test-data-nullable-strings
+                                         {:filter [:= $mystring "foo"]
+                                          :aggregation [:count]}))
+      qp.test/first-row last))
+
 (datasets/expect-with-driver :clickhouse
   [[1 "Я_1"]
    [3 "Я_2"]