提交 3dd3d652 编写于 作者: M Mars Liu

修正查询计数的答案错误

上级 79a63904
{ {
"node_id": "mysql-ac3c072bc54749bdb82324f2b203890d", "node_id": "mysql-ac3c072bc54749bdb82324f2b203890d",
"keywords": ["count", "计数"], "keywords": [
"count",
"计数"
],
"children": [], "children": [],
"export": [ "export": [
"count.json" "count.json"
......
...@@ -33,7 +33,12 @@ from items; ...@@ -33,7 +33,12 @@ from items;
## 答案 ## 答案
``` ```
3, 4 +----------+-------------+
| count(*) | count(item) |
+----------+-------------+
| 4 | 3 |
+----------+-------------+
1 row in set (0.00 sec)
``` ```
## 选项 ## 选项
...@@ -41,29 +46,54 @@ from items; ...@@ -41,29 +46,54 @@ from items;
### A ### A
``` ```
4, NULL +----------+-------------+
| count(*) | count(item) |
+----------+-------------+
| 4 | NULL |
+----------+-------------+
1 row in set (0.00 sec)
``` ```
### B ### B
``` ```
3, 3 +----------+-------------+
| count(*) | count(item) |
+----------+-------------+
| 3 | 3 |
+----------+-------------+
1 row in set (0.00 sec)
``` ```
### C ### C
``` ```
1, 0 +----------+-------------+
| count(*) | count(item) |
+----------+-------------+
| 4 | 4 |
+----------+-------------+
1 row in set (0.00 sec)
``` ```
### D ### D
``` ```
NULL, NULL +----------+-------------+
| count(*) | count(item) |
+----------+-------------+
| NULL | NULL |
+----------+-------------+
1 row in set (0.00 sec)
``` ```
### E ### E
``` ```
4, 4 +----------+-------------+
| count(*) | count(item) |
+----------+-------------+
| 4 | 0 |
+----------+-------------+
1 row in set (0.00 sec)
``` ```
\ No newline at end of file
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