[shardingsphere] branch master updated: fix doc for sql support (#7962)

[pa...@apache.org]

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panjuan pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/shardingsphere.git


The following commit(s) were added to refs/heads/master by this push:
     new 2d61007  fix doc for sql support (#7962)
2d61007 is described below

commit 2d6100748de7f9883413766e25b1bdbdb4d11c9a
Author: JingShang Lu <lu...@apache.org>
AuthorDate: Tue Nov 3 14:29:39 2020 +0800

    fix doc for sql support (#7962)
    
    * fix doc for sql support
    
    * fix
    
    * fix
    
    * fix
    
    * fix
    
    * fix
    
    * Update sql.cn.md
---
 docs/document/content/features/sharding/use-norms/sql.cn.md | 12 +++++++++---
 docs/document/content/features/sharding/use-norms/sql.en.md | 12 +++++++++---
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/docs/document/content/features/sharding/use-norms/sql.cn.md b/docs/document/content/features/sharding/use-norms/sql.cn.md
index ef9de86..7d1d4d8 100644
--- a/docs/document/content/features/sharding/use-norms/sql.cn.md
+++ b/docs/document/content/features/sharding/use-norms/sql.cn.md
@@ -49,20 +49,26 @@ tbl_name [AS] alias] [index_hint_list]
 
 ### 路由至多数据节点
 
-不支持CASE WHEN、HAVING、UNION (ALL)，有限支持子查询。
+部分支持CASE WHEN
+* `CASE WHEN` 中包含子查询不支持
+* `CASE WHEN` 中使用逻辑表名不支持（请使用表别名）
+不支持 HAVING、UNION (ALL)
+
+部分支持子查询
+* 子查询中必须包含分片键，且分片键必须和父查询中的分片键一致
 
 除了分页子查询的支持之外(详情请参考[分页](/cn/features/sharding/use-norms/pagination))，也支持同等模式的子查询。无论嵌套多少层，ShardingSphere都可以解析至第一个包含数据表的子查询，一旦在下层嵌套中再次找到包含数据表的子查询将直接抛出解析异常。
 
 例如，以下子查询可以支持：
 
 ```sql
-SELECT COUNT(*) FROM (SELECT * FROM t_order o)
+SELECT COUNT(*) FROM (SELECT * FROM t_order o where id>10) where id>10;
 ```
 
 以下子查询不支持：
 
 ```sql
-SELECT COUNT(*) FROM (SELECT * FROM t_order o WHERE o.id IN (SELECT id FROM t_order WHERE status = ?))
+SELECT COUNT(*) FROM (SELECT * FROM t_order o)
 ```
 
 简单来说，通过子查询进行非功能需求，在大部分情况下是可以支持的。比如分页、统计总数等；而通过子查询实现业务查询当前并不能支持。
diff --git a/docs/document/content/features/sharding/use-norms/sql.en.md b/docs/document/content/features/sharding/use-norms/sql.en.md
index 119f6a5..fc7eb13 100644
--- a/docs/document/content/features/sharding/use-norms/sql.en.md
+++ b/docs/document/content/features/sharding/use-norms/sql.en.md
@@ -49,20 +49,26 @@ tbl_name [AS] alias] [index_hint_list]
 
 ### Route to multiple data nodes
 
-Do not support CASE WHEN, HAVING and UNION (ALL) and partly available sub-query.
+Partially support CASE WHEN
+* `CASE WHEN` containing sub-query is not supported
+* `CASE WHEN` containing logical-table is not supported(please use alias of table)
+
+Do not support HAVING and UNION (ALL) 
+Partly available sub-query
+* If there is a subquery, it needs sharding key condition and be consistent with the parent query.
 
 Support not only pagination sub-query (see [pagination](https://shardingsphere.apache.org/document/current/cn/features/sharding/usage-standard/pagination) for more details), but also sub-query with the same mode. No matter how many layers are nested, ShardingSphere can parse to the first sub-query that contains data table. Once it finds another sub-query of this kind in the sub-level nested, it will directly throw a parsing exception.
 
 For example, the following sub-query is available:
 
 ```sql
-SELECT COUNT(*) FROM (SELECT * FROM t_order o)
+SELECT COUNT(*) FROM (SELECT * FROM t_order o where id>10) where id>10;
 ```
 
 The following sub-query is unavailable:
 
 ```sql
-SELECT COUNT(*) FROM (SELECT * FROM t_order o WHERE o.id IN (SELECT id FROM t_order WHERE status = ?))
+SELECT COUNT(*) FROM (SELECT * FROM t_order o)
 ```
 
 To be simple, through sub-query, non-functional requirements are available in most cases, such as pagination, sum count and so on; but functional requirements are unavailable for now.