摘要:
SQL: COUNT FunctionThe COUNT function returns the number of rows in a query.The syntax for the COUNT function is:SELECT COUNT(expression)FROM tablesWHERE predicates;Note:The COUNT function will only count those records in which the field in the brackets is NOT NULL.For example, if you have the follo 阅读全文
posted @ 2012-04-08 13:18 郭 弈楠 阅读(154) 评论(0) 推荐(0) 编辑