correct handling null values in update keys

packages/datalib/src/ChangeSet.ts

@@ -1,5 +1,14 @@
 import _ from 'lodash';
-import { Command, Insert, Update, Delete, UpdateField, Condition, AllowIdentityInsert } from 'dbgate-sqltree';
+import {
+  Command,
+  Insert,
+  Update,
+  Delete,
+  UpdateField,
+  Condition,
+  AllowIdentityInsert,
+  Expression,
+} from 'dbgate-sqltree';
 import { NamedObjectInfo, DatabaseInfo } from 'dbgate-types';
 
 export interface ChangeSetItem {
@@ -262,12 +271,9 @@ function changeSetInsertToSql(
 }
 
 export function extractChangeSetCondition(item: ChangeSetItem, alias?: string): Condition {
-  return {
+  function getColumnCondition(columnName: string): Condition {
-    conditionType: 'and',
+    const value = item.condition[columnName];
-    conditions: _.keys(item.condition).map(columnName => ({
+    const expr: Expression = {
-      conditionType: 'binary',
-      operator: '=',
-      left: {
       exprType: 'column',
       columnName,
       source: {
@@ -277,12 +283,27 @@ export function extractChangeSetCondition(item: ChangeSetItem, alias?: string):
         },
         alias,
       },
-      },
+    };
+    if (value == null) {
+      return {
+        conditionType: 'isNull',
+        expr,
+      };
+    } else {
+      return {
+        conditionType: 'binary',
+        operator: '=',
+        left: expr,
         right: {
           exprType: 'value',
-        value: item.condition[columnName],
+          value,
         },
-    })),
+      };
+    }
+  }
+  return {
+    conditionType: 'and',
+    conditions: _.keys(item.condition).map(columnName => getColumnCondition(columnName)),
   };
 }