bco 发表于 2016-10-31 02:16:55

SQL SERVER 的小技巧

http://zu14.iyunv.com/Images/OutliningIndicators/None.gif运算符的优先顺序
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif当一个复杂的表达式有多个运算符时,运算符优先性决定执行运算的先后次序。执行的顺序可能严重地影响所得到的值。
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif运算符有下面这些优先等级。在较低等级的运算符之前先对较高等级的运算符进行求值。 
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif+(正)、-(负)、~(按位 NOT)
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif*(乘)、/(除)、%(模)
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif+(加)、(+ 串联)、-(减)
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif=,  >,  <,  >=,  <=,  <>,  !=,  !>,  !< 比较运算符
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif^(位异或)、&(位与)、|(位或)
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gifNOT
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gifAND
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gifALL、ANY、BETWEEN、IN、LIKE、OR、SOME
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif=(赋值) 
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif


运算符, 不常用的 二进制 运算符,在某些方面也有独特的用处,例如: 正^正=正 ... ...

http://zu14.iyunv.com/Images/OutliningIndicators/None.gif--建一张和某(几)张表结构相同的表
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gifSELECT * INTO [新表] FROM [源表] WHERE 1 = 0
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/ExpandedBlockStart.gifhttp://zu14.iyunv.com/Images/OutliningIndicators/ContractedBlock.gif/**//*此种方式建立的表,只有基本的结构,主键等的附加信息都没有了*/


http://zu14.iyunv.com/Images/OutliningIndicators/ExpandedBlockStart.gifhttp://zu14.iyunv.com/Images/OutliningIndicators/ContractedBlock.gif/**//* 一些特殊的排序方法 */
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif-- 1. 
http://zu14.iyunv.com/Images/OutliningIndicators/None.gifselect * from table
http://zu14.iyunv.com/Images/OutliningIndicators/None.giforder by 
http://zu14.iyunv.com/Images/OutliningIndicators/None.gifcase id 
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif when 4 then 1
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif when 5 then 0
http://zu14.iyunv.com/Images/OutliningIndicators/None.gifend
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif-- 2.
http://zu14.iyunv.com/Images/OutliningIndicators/None.gifSELECT * FROM table 
http://zu14.iyunv.com/Images/OutliningIndicators/None.gifORDER BY id % 5
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif-- 3.
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gifSELECT * FROM table
http://zu14.iyunv.com/Images/OutliningIndicators/None.gifORDER BY RIGHT(id, 3)
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif
http://zu14.iyunv.com/Images/OutliningIndicators/None.gif-------------------------------
http://zu14.iyunv.com/Images/OutliningIndicators/ExpandedBlockStart.gifhttp://zu14.iyunv.com/Images/OutliningIndicators/ContractedBlock.gif/**//* 总之,就是一些变通的思路 */

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