Fixed issue with download spreadsheet export and selection of all records.

CHANGELOG.md

 # Version 1.93 (not yet released)
 
+* Fixed issue with download spreadsheet export and selection of all records.
+
 # Version 1.92
 
 * Fixed issue #136: getSort also NULL as return

Civi/DataProcessor/DataFlow/SqlDataFlow/SimpleWhereClause.php

@@ -124,12 +124,12 @@ class SimpleWhereClause extends AbstractWhereClause implements WhereClauseInterf
       case '!=':
         return "($fieldStatement $this->operator $this->value OR `$this->table_alias`.`$this->field` IS NULL)";
       case 'IS NULL':
-        if ($this->valueType == 'Timestamp') {
+        if ($this->valueType == 'Timestamp' || $this->valueType == 'Date') {
           return "$fieldStatement $this->operator $this->value";
         }
         return "(`$this->table_alias`.`$this->field` $this->operator OR `$this->table_alias`.`$this->field` = '')";
       case 'IS NOT NULL':
-        if ($this->valueType == 'Timestamp') {
+        if ($this->valueType == 'Timestamp' || $this->valueType == 'Date') {
           return "$fieldStatement $this->operator $this->value";
         }
         return "(`$this->table_alias`.`$this->field` $this->operator AND `$this->table_alias`.`$this->field` != '')";