executescalar mysql_ ExecuteScalar（）

Hello everyone , I meet you again , I'm your friend, Quan Jun .

ExecuteScalar() The purpose of the method is to ：

Execute the query , And return the first column of the first row in the result set returned by the query . All other columns and rows are ignored .

When its return value object, If you want to judge whether a piece of data exists in the database, you can use this method ,

//sql writing

private string m_str_variationInfo = @”SELECT variationinfoMngno

FROM sellersandvariationmngtbl

WHERE sellerCD= @sellerCD

“;

// Handle

MySqlParameter[] MySqlParameter = new MySqlParameter[1];

MySqlParameter[0] = new MySqlParameter(“@sellerCD”, prm_sellerCD);

object val = DataAccess.ExecuteScalar(prm_con, CommandType.Text, m_str_variationInfo, MySqlParameter);

return val;

Judge val Whether it is empty can be read-only. Does the data save exist .

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ExecuteScalar() The purpose of the method is to : Execute the query , And return the first column of the first row in the result set returned by the query . All other columns and rows are ignored . 1. Back to a object type , That is to say, it is the base class of all data types , According to the se …

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