Merge pull request #6095 from sundy-li/group-constant

fix(groupby): support group by constant string
databendlabs · Jun 21, 2022 · 7b434be · 7b434be
2 parents 48135f5 + b6c5615
commit 7b434be
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Showing 3 changed files with 9 additions and 3 deletions.
diff --git a/common/datablocks/src/kernels/data_block_group_by_hash.rs b/common/datablocks/src/kernels/data_block_group_by_hash.rs
@@ -212,11 +212,11 @@ impl HashMethod for HashMethodSingleString {
     ) -> Result<Vec<&'a [u8]>> {
         debug_assert!(group_columns.len() == 1);
         let column = group_columns[0];
-        let str_column: &StringColumn = Series::check_get(column)?;
-
+        // may have constant case
+        let str_column = Vu8::try_create_viewer(column)?;
         let mut values = Vec::with_capacity(rows);
         for row in 0..rows {
-            values.push(str_column.get_data(row));
+            values.push(str_column.value_at(row));
         }
         Ok(values)
     }

diff --git a/tests/suites/0_stateless/03_dml/03_0003_select_group_by.result b/tests/suites/0_stateless/03_dml/03_0003_select_group_by.result
@@ -60,3 +60,5 @@ NULL	2	3
 2	1	[]
 4	3	[1, 2, 3]
 6	5	[4, 5, 6]
+10
+10
diff --git a/tests/suites/0_stateless/03_dml/03_0003_select_group_by.sql b/tests/suites/0_stateless/03_dml/03_0003_select_group_by.sql
@@ -77,4 +77,8 @@ INSERT INTO t_array VALUES(1, []),
 
 SELECT max(id), min(id), arr FROM t_array GROUP BY arr ORDER BY arr ASC;
 
+-- group by constant string
+select count() from numbers(10) group by 'ab';
+select count() from numbers(10) group by to_nullable('ab');
+
 DROP TABLE t_array;