表执行条件LEC ？
您可通过定义具有过滤条件的虚拟表，来有效地减少从源所读取记录的数量，并减小规则的总执行时间。
You can effectively reduce the number of records that are read from the source, and reduce the overall execution time of a rule, by defining a virtual table with a filter condition.
还可以通过使用WHERE条件、ORDER BY、GROUP BY 子句执行过滤操作，或者执行常规基表适用的其他操作。
You can also perform operations such as filtering, using WHERE conditions, ORDER BY, GROUP BY, and other operations that would be possible with a regular base table.
在某些条件下，会在merge语句执行过程中创建内部临时表，如清单7所示。
Under certain conditions, internal temporary tables are created during the execution of the merge statement, as shown in Listing 7.
如果，我改变连接条件和任何表副本同时执行相同的，那么同样将被传播到后续的加入。
If, I change the join condition and any table duplicates while performing the same, then the same will be propagated to the subsequent joins.
如果，我改变连接条件和任何表副本同时执行相同的，那么同样将被传播到后续的加入。
If, I change the join condition and any table duplicates while performing the same, then the same will be propagated to the subsequent joins.
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