partitioned-table: create strictly increasing range columns partition (…

…pingcap#18353)

partitioned-table.md

@@ -169,6 +169,23 @@ Range partitioning is particularly useful when one or more of the following cond
 
 Range COLUMNS partitioning is a variant of Range partitioning. You can use one or more columns as partitioning keys. The data types of partition columns can be integer, string (`CHAR` or `VARCHAR`), `DATE`, and `DATETIME`. Any expressions, such as non-COLUMNS partitioning, are not supported.
 
+Like Range partitioning, Range COLUMNS partitioning also requires the partition ranges to be strictly increasing. The partition definition in the following example is not supported:
+
+```sql
+CREATE TABLE t(
+    a int,
+    b datetime,
+    c varchar(8)
+) PARTITION BY RANGE COLUMNS(`c`,`b`)
+(PARTITION `p20240520A` VALUES LESS THAN ('A','2024-05-20 00:00:00'),
+ PARTITION `p20240520Z` VALUES LESS THAN ('Z','2024-05-20 00:00:00'),
+ PARTITION `p20240521A` VALUES LESS THAN ('A','2024-05-21 00:00:00'));
+```
+
+```
+Error 1493 (HY000): VALUES LESS THAN value must be strictly increasing for each partition
+```
+
 Suppose that you want to partition by name, and drop old and invalid data, then you can create a table as follows:
 
 ```sql