generated

data/3.MySQL高阶/5.设计优化/1.生成列/config.json

@@ -3,5 +3,8 @@
   "keywords": [],
   "keywords_must": [],
   "keywords_forbid": [],
-  "group": 0
+  "group": 2,
+  "export": [
+    "generated.json"
+  ]
 }
\ No newline at end of file

data/3.MySQL高阶/5.设计优化/1.生成列/generated.json

+{
+  "type": "code_options",
+  "author": "ccat",
+  "source": "generated.md",
+  "notebook_enable": false,
+  "exercise_id": "e09151d6764e4e14bd088c858db0a0e3"
+}
\ No newline at end of file

data/3.MySQL高阶/5.设计优化/1.生成列/generated.md

+# 生成列
+
+Joe 需要为 Points 表
+
+```mysql
+create table points(
+    id int primary key auto_increment,
+    x float,
+    y float
+)
+```
+
+增加一个生成列，保存每个点的模（modulus），即 `√(x^2 + y^2)` 。下面哪个操作是正确的？
+
+## 答案
+
+```mysql
+alter table points add modulus double generated always as (sqrt(x*x + y*y));
+```
+
+## 选项
+
+### A
+
+```mysql
+create generated modulus on table points as (sqrt(x*x + y*y));
+```
+
+### B
+
+```mysql
+alter table points add modulus generated always as (sqrt(x*x + y*y));
+```
+
+### C
+
+```mysql
+alter table points add modulus float generated sqrt(x*x + y*y);
+```

data/tree.json

@@ -2233,7 +2233,7 @@
                       "children": [],
                       "keywords_must": [],
                       "keywords_forbid": [],
-                      "group": 0
+                      "group": 2
                     }
                   },
                   {