如何计算表格中没有的值? [英] how to count no of values in a table?
本文介绍了如何计算表格中没有的值?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
此代码给出了一个异常,指出"incorrect syntax near the word DISTINCT"
此查询有什么问题?
this code gives a exception saying that "incorrect syntax near the word DISTINCT"
what is wrong in this query?
private SqlConnection con;
private SqlCommand cmd;
private SqlDataReader dr;
openConnection();
string qry1 = "SELECT COUNT (V1) FROM votes GROUP BY DISTINCT V1";
cmd = new SqlCommand(qry1, con);
dr = cmd.ExecuteReader();
while (dr.Read())
{
count = dr[0].ToString();
}
int ans= Convert.ToInt32(count);
MessageBox.Show(Convert.ToString(ans));
closeConnection();
推荐答案
SELECT COUNT (DISTINCT V1) FROM votes group by v1;
尝试一下...
TRY THIS...
更改此项:
change this:
string qry1 = "SELECT COUNT (V1) FROM votes GROUP BY DISTINCT V1";
与此:
with this:
string qry1 = "SELECT COUNT (V1) FROM votes GROUP BY V1";
希望这会有所帮助:)
hope this helps :)
尝试一下
从投票中选择DISTINCT COUNT(V1),按V1分组
TRY THIS
SELECT DISTINCT COUNT (V1) FROM votes GROUP BY V1
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