有人可以帮助澄清限制运营商吗？
我理解Sybase restrict运算符用于根据列计算表达式。但我仍然无法在查询计划中找出RESTRICT运算符的确切含义。
例如，下面是我的sql的查询计划片段。 RESTRICT运算符（VA = 1）（4）（0）（0）（0）（0）：（4）（0）（0）（0）（0）是什么意思？
10 operator(s) under root
|ROOT:EMIT Operator (VA = 10)
|
| |SCALAR AGGREGATE Operator (VA = 9)
| | Evaluate Ungrouped COUNT AGGREGATE.
| |
| | |N-ARY NESTED LOOP JOIN Operator (VA = 8) has 7 children.
| | |
| | | |RESTRICT Operator (VA = 1)(4)(0)(0)(0)(0)
| | | |
| | | | |SCAN Operator (VA = 0)
| | | | | FROM TABLE
| | | | | trade
| | | | | t
| | | | | Index : i1
| | | | | Forward Scan.
| | | | | Positioning by key.
| | | | | Keys are:
| | | | | order_number ASC
| | | | | Using I/O Size 16 Kbytes for index leaf pages.
| | | | | With LRU Buffer Replacement Strategy for index leaf pages.
| | | | | Using I/O Size 16 Kbytes for data pages.
| | | | | With LRU Buffer Replacement Strategy for data pages.
| | |
| | | |SCAN Operator (VA = 2)
| | | | FROM TABLE
| | | | product
| | | | mp
| | | | Index : mp
| | | | Forward Scan.
| | | | Positioning by key.
| | | | Keys are:
| | | | prod_id ASC
| | | | Using I/O Size 16 Kbytes for index leaf pages.
| | | | With LRU Buffer Replacement Strategy for index leaf pages.
| | | | Using I/O Size 16 Kbytes for data pages.
| | | | With LRU Buffer Replacement Strategy for data pages.
| | |
| | | |SCAN Operator (VA = 3)
| | | | FROM TABLE
| | | | Accounts
| | | | a
| | | | Index : i2
| | | | Forward Scan.
| | | | Positioning by key.
| | | | Index contains all needed columns. Base table will not be read.
| | | | Keys are:
| | | | account ASC
| | | | Using I/O Size 16 Kbytes for index leaf pages.
| | | | With LRU Buffer Replacement Strategy for index leaf pages.
答案 0 :(得分：1)
showplan输出的一部分，就像运算符后面的数字一样，是ASE优化器的内部。没有关于这些的文档信息，并且包含此信息以帮助技术支持解决问题。 'VA = n'部分仅反映查询计划中每个运算符的唯一数字'n'。