我一直在尝试使用Dapper的WHERE IN
子句来处理IEnumerable<string>
,但一直未能成功。
文档中确实提到支持IEnumerable<int>
用于WHERE IN
,但我甚至不能让它正常工作。
Dapper允许您传递IEnumerable<int>,并自动参数化查询。
我一直收到的错误消息是Sql语法错误:Incorrect syntax near ','.
我编写了一些测试代码,希望能够演示我的目标。
string connString = "Server=*.*.*.*;Database=*;User Id=*;Password=*;";
string sqlStringIn = @"SELECT StringText FROM
(SELECT 1 ID, 'A' StringID, 'This is a test' StringText
UNION SELECT 2 ID, 'B' StringID, 'Another test' StringText
UNION SELECT 3 ID, 'C' StringID, 'And another' StringText
UNION SELECT 4 ID, 'D' StringID, 'and again' StringText
UNION SELECT 5 ID, 'E' StringID, 'yet again' StringText) data
WHERE StringId IN (@str)";
string sqlIntegerIn = @"SELECT StringText FROM
(SELECT 1 ID, 'A' StringID, 'This is a test' StringText
UNION SELECT 2 ID, 'B' StringID, 'Another test' StringText
UNION SELECT 3 ID, 'C' StringID, 'And another' StringText
UNION SELECT 4 ID, 'D' StringID, 'and again' StringText
UNION SELECT 5 ID, 'E' StringID, 'yet again' StringText) data
WHERE ID IN (@integer)";
using (SqlConnection conn = new SqlConnection(connString))
{
conn.Open();
List<int> integers = new List<int>{ 1, 2, 3 };
List<string> strings = new List<string> { "A", "B", "C" };
var parameters = new {str = strings, integer = integers };
//fails here
IEnumerable<string> intTest = conn.Query<string>(sqlIntegerIn, parameters, commandType: System.Data.CommandType.Text);
//and here
IEnumerable<string> stringTest = conn.Query<string>(sqlStringIn, parameters, commandType: System.Data.CommandType.Text);
}