华康效率手册是您最好的助手！
应用可靠性预计手册计算了各单元的工作失效率。
The failure rate for each unit is calculated according to reliability handbook.
在普通V带传动设计中，传统设计方法存在查找手册工作量大、效率低的不足，且所得设计方案未必是最佳设计方案。
In the design of classical V-belt driving, the traditional method has disadvantages of low efficiency and the great work load of looking up manual. In addition, its design may not be the best.
查看官方手册，也说rand（）放在ORDERBY 子句中会被执行多次，自然效率及很低。
You cannot use a column with RAND() values in an ORDER BY clause, because ORDER BY would evaluate the column multiple times.
查看官方手册，也说rand（）放在ORDERBY 子句中会被执行多次，自然效率及很低。
You cannot use a column with RAND() values in an ORDER BY clause, because ORDER BY would evaluate the column multiple times.
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