feat: add sql solution to lc problems: No.0626

No.0626.Exchange Seats

Author: YangFong

solution/0600-0699/0626.Exchange Seats/README.md

@@ -65,14 +65,31 @@ Seat 表:
 
 ### **SQL**
 
-```
+```sql
 SELECT
-    s1.id, COALESCE(s2.student, s1.student) AS student
+	s1.id,
+	COALESCE ( s2.student, s1.student ) AS student 
 FROM
-    seat s1
-        LEFT JOIN
-    seat s2 ON (s1.id+1)^1-1 = s2.id
-ORDER BY s1.id;
+	seat s1
+	LEFT JOIN seat s2 ON ( s1.id + 1 ) ^ 1 - 1 = s2.id 
+ORDER BY
+	s1.id;
+```
+
+```sql
+SELECT 
+    id + (
+        CASE 
+            WHEN id % 2 = 1 AND id != (SELECT MAX(id) FROM seat) THEN 1
+			WHEN id % 2 = 0 THEN -1
+			ELSE 0
+		END
+    ) AS id, 
+    student
+FROM 
+    seat
+ORDER BY 
+	id;
 ```
 
 <!-- tabs:end -->

solution/0600-0699/0626.Exchange Seats/README_EN.md

@@ -61,14 +61,31 @@ Note that if the number of students is odd, there is no need to change the last
 
 ### **SQL**
 
-```
+```sql
 SELECT
-    s1.id, COALESCE(s2.student, s1.student) AS student
+	s1.id,
+	COALESCE ( s2.student, s1.student ) AS student 
 FROM
-    seat s1
-        LEFT JOIN
-    seat s2 ON (s1.id+1)^1-1 = s2.id
-ORDER BY s1.id;
+	seat s1
+	LEFT JOIN seat s2 ON ( s1.id + 1 ) ^ 1 - 1 = s2.id 
+ORDER BY
+	s1.id;
+```
+
+```sql
+SELECT 
+    id + (
+        CASE 
+            WHEN id % 2 = 1 AND id != (SELECT MAX(id) FROM seat) THEN 1
+			WHEN id % 2 = 0 THEN -1
+			ELSE 0
+		END
+    ) AS id, 
+    student
+FROM 
+    seat
+ORDER BY 
+	id;
 ```
 
 <!-- tabs:end -->

solution/0600-0699/0626.Exchange Seats/Solution.sql

@@ -1,7 +1,8 @@
 SELECT
-    s1.id, COALESCE(s2.student, s1.student) AS student
+	s1.id,
+	COALESCE ( s2.student, s1.student ) AS student 
 FROM
-    seat s1
-        LEFT JOIN
-    seat s2 ON (s1.id+1)^1-1 = s2.id
-ORDER BY s1.id;
+	seat s1
+	LEFT JOIN seat s2 ON ( s1.id + 1 ) ^ 1 - 1 = s2.id 
+ORDER BY
+	s1.id;