SQL that routes to single data nodes; SQL routing to multiple data nodes is divided, because of complexity issues, into three conditions: stable support, experimental support, and no support. Stable Support sub‐query ‐ Logic names are used in CASE WHEN( Please use an alias) Pagination Query Due to the complexity of paging queries, there are currently some paging queries that are not supported for Oracle and environment similar to the production environment is too high. It is usually impossible to simulate the complexity and data of the production environment. So, it is the better way to use the production environment

SQL that routes to single data nodes; SQL routing to multiple data nodes is divided, because of complexity issues, into three conditions: stable support, experimental support, and no support. Stable Support sub‐query ‐ Logic names are used in CASE WHEN( Please use an alias) Pagination Query Due to the complexity of paging queries, there are currently some paging queries that are not supported for Oracle and environment similar to the production environment is too high. It is usually impossible to simulate the complexity and data of the production environment. So, it is the better way to use the production environment

SQLServer, Oracle, openGauss and SQL that conform to the SQL92 specification. However, due to the complexity of SQL syntax, there are still a little of SQL do not support yet. This chapter has listed unsupported queries of MySQL, PostgreSQL and Oracle; partly support SQLServer pagi‐ nation query due to its complexity. 4.2. Sharding 38 Apache ShardingSphere document, v5.0.0 Pagination Performance Performance routed to. For the item to be sorted which has its own order, merger ordering only has the time complexity of O(nlogn), with a very low performance consumption. Secondly, ShardingSphere further optimizes

SQL that routes to single data nodes; SQL routing to multiple data nodes is divided, because of complexity issues, into three conditions: stable support, experimental support, and no support. Stable Support sub‐query ‐ Logic names are used in CASE WHEN( Please use an alias) Pagination Query Due to the complexity of paging queries, there are currently some paging queries that are not supported for Oracle and environment similar to the production environment is too high. It is usually impossible to simulate the complexity and data of the production environment. So, it is the better way to use the production environment

SQL that routes to single data nodes; SQL routing to multiple data nodes is divided, because of complexity issues, into three conditions: stable support, experimental support, and no support. Stable Support sub‐query ‐ Logic names are used in CASE WHEN( Please use an alias) Pagination Query Due to the complexity of paging queries, there are currently some paging queries that are not supported for Oracle and environment similar to the production environment is too high. It is usually impossible to simulate the complexity and data of the production environment. So, it is the better way to use the production environment

FROM t_order_0 WHERE order_id IN (1, 2); SELECT * FROM t_order_1 WHERE order_id IN (1, 2); The complexity and performance of the joint query are comparable with those of single‐table query. For instance queries of MySQL, PostgreSQL and Oracle; partly support SQLServer pagi‐ nation query due to its complexity. Pagination Performance Performance Bottleneck Pagination with query offset too high can lead routed to. For the item to be sorted which has its own order, merger ordering only has the time complexity of O(n), with a very low performance consumption. 3.1. Sharding 57 Apache ShardingSphere document

SQLServer, Oracle, openGauss and SQL that conform to the SQL92 specification. However, due to the complexity of SQL syntax, there are still a little of SQL do not support yet. This chapter has listed unsupported queries of MySQL, PostgreSQL and Oracle; partly support SQLServer pagi‐ nation query due to its complexity. 4.3. Sharding 41 Apache ShardingSphere document, v5.1.1 Pagination Performance Performance routed to. For the item to be sorted which has its own order, merger ordering only has the time complexity of O(mn(log m)), and the number of shard m is generally small enough to be considered as O(n)

SQLServer, Oracle, openGauss and SQL that conform to the SQL92 specification. However, due to the complexity of SQL syntax, there are still a little of SQL do not support yet. This chapter has listed unsupported queries of MySQL, PostgreSQL and Oracle; partly support SQLServer pagi‐ nation query due to its complexity. 4.3. Sharding 42 Apache ShardingSphere document, v5.1.2 Pagination Performance Performance routed to. For the item to be sorted which has its own order, merger ordering only has the time complexity of O(mn(log m)), and the number of shard m is generally small enough to be considered as O(n)