wy1433 opened a new issue, #37297:
URL: https://github.com/apache/shardingsphere/issues/37297
## Feature Request
### Is your feature request related to a problem?
Yes. Currently, ShardingSphere handles INSERT statements with batch value
splitting - each value in an INSERT INTO ... VALUES clause is individually
routed and then merged based on target data nodes.
However, SELECT queries with IN expressions (e.g., `SELECT * FROM t_order
WHERE order_id IN (1, 2, 3)`) are not handled the same way.
When executing a SELECT query with IN expression on a sharding key, if
different values route to different shards, the current implementation sends
all IN values to all matched shards, resulting in
unnecessary data transfer and processing.
### Describe the feature you would like.
Implement IN query batch split rewrite similar to INSERT VALUES handling:
1. Parse IN expression values and route each value individually
2. Track which values route to which data nodes (like `originalDataNodes`
for INSERT)
3. During SQL rewrite, filter IN values per route unit to only include
values that route to that specific shard
**Key Components:**
- **InValueContext**: Store IN expression structural information (similar
to InsertValueContext)
- **ShardingInValuesToken**: Token for rewriting IN values based on route
unit
- **ShardingInValuesTokenGenerator**: Generate tokens for IN expressions
- **ShardingStandardRouteEngine**: Add logic to split IN query conditions
**Expected Behavior:**
Before (current):
- All shards receive: `SELECT * FROM t_order WHERE order_id IN (1, 2, 3)`
After (proposed):
- ds_0 receives: `SELECT * FROM t_order_0 WHERE order_id IN (1)`
- ds_1 receives: `SELECT * FROM t_order_1 WHERE order_id IN (2, 3)`
**Benefits:**
1. Reduced data transfer between shards
2. More efficient query execution per shard
3. Consistent behavior between INSERT and SELECT sharding optimizations"
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