摘要： Microsoft Script Debugger —— Companion.JS need to install this Companion.JS —— Javascript debugger for IE , like Console API feature IE Developer Toolbar —— Firebug for IE ... 阅读全文

摘要： ISNULL是判断是否为NULL 而NULLIF是把值换成NULL COALESCE是用别的来代替NULL SELECT employee_id,first_name,last_name,NULLIF (SALES_QUOTA,-1) as Quota FROM employees 就是把-1变成 NULL COALESCE(表达式1,表达式2,....表达式n) 从前到后,谁不是NULL... 阅读全文