我正在尝试在更新多个记录时有效地使用UPDATE
查询(而不是为每个Id
循环)。
我有这个简单的方法:
public static async Task EfficientlyUpdateSentTimeforSomeTicketsAsync(List<int> Ids)
{
var parameters = Ids.Select((id, index) => new SqlParameter(string.Format("@p{0}", index), id));
var parameterNames = string.Join(", ", parameters.Select(p => p.ParameterName));
var query = string.Format("Update [TicketQueueTable] Set SentDatetime = {1} WHERE TicketQueueID IN ({0})", parameterNames, DateTime.Now);
try
{
using (var db = GetDbContext())
{
var affectedRows = await db.Database.ExecuteSqlCommandAsync(query, parameters.ToArray());
}
}
catch (Exception ex)
{
await LogErrorAsync(ex);
throw ex;
}
}
我从以下SO问题获得帮助:https://stackoverflow.com/a/43969812/8644294,但无法完成这项工作。它让我大吃一惊,说:
[2附近的语法不正确]
为简单起见,我现在要发送的ID为new List<int>() { 1, 2 }
。
谢谢您的时间。
您正在创建的字符串看起来像这样
Update [TicketQueueTable] Set SentDatetime = 3/6/2020 2:30:18 AM WHERE TicketQueueID IN (@p0, @p1)
如果尝试使用类似SQL Server Management Studio的sql工具执行该命令,则会出现此错误。
Msg 102, Level 15, State 1, Line 1
Incorrect syntax near '2'.
加上凌晨2:30:18的2加上红色下划线。
您有两个选择:
var query = string.Format("Update [TicketQueueTable] Set SentDatetime = '{1}' WHERE TicketQueueID IN ({0})", parameterNames, DateTime.Now);
var query = string.Format("Update [TicketQueueTable] Set SentDatetime = GETDATE() WHERE TicketQueueID IN ({0})", parameterNames, DateTime.Now); // GETDATE() for MSSQL NOW() for MySQL
public static async Task EfficientlyUpdateSentTimeforSomeTicketsAsync(List<int> Ids)
{
var parameters = Ids.Select((id, index) => new SqlParameter(string.Format("@p{0}", index), id)).ToList();
var parameterNames = string.Join(", ", parameters.Select(p => p.ParameterName));
var query = string.Format("Update [TicketQueueTable] Set SentDatetime = @p{1} WHERE TicketQueueID IN ({0})", parameterNames, parameters.Count());
parameters.Add(new SqlParameter($"@p{parameters.Count()}", DateTime.Now));
try
{
using (var db = GetDbContext())
{
var affectedRows = await db.Database.ExecuteSqlCommandAsync(query, parameters.ToArray());
}
}
catch (Exception ex)
{
await LogErrorAsync(ex);
throw ex;
}
}
诸如此类:(我没有测试,可能有错字)
var parameterNames = string.Join(", ", Ids.Select(p => "("+ x.id.ToString()+")"));
var query = string.Format(@"Update TicketQueueTable
Set SentDatetime = '{1}'
FROM TicketQueueTable
JOIN (
VALUES
{0}
) AS L(ID) ON TicketQueueTable.Ticket.TicketQueueID = L.ID;", parameterNames, DateTime.Now)
如果要使用参数(应使用),则将其设为表参数,并在表中包含值列表,然后将其连接。