Question

我正在尝试使用Dapper确定是否可以将对象列表插入表中，而且还要进行某种检查以查看应包含哪些数据。

var data = new List<TestInsertDataDto>
{
    new TestInsertDataDto { InsertId = 1, Value = 2 },
    new TestInsertDataDto { InsertId = 2, Value = 3 },
    new TestInsertDataDto { InsertId = 3, Value = 6 }
};

await connection.ExecuteAsync(@"
    INSERT INTO test_data (insertid, value)
    VALUES (@InsertId, @Value)
    -- I'd like to do a row per row check here to determine if the row should be
    -- inserted or if this row for some reason shouldn't be inserted. This check
    -- requires a query on the test_data table and a join on another table.", data)
;

Answer 1

您可以使用EXISTS或NOT EXISTS根据另一个查询有条件地插入记录。
看起来像：

INSERT INTO test_data (insertid, value)
SELECT @InsertId, @Value
WHERE EXISTS (
    SELECT *
    FROM test_data
    WHERE -- some condition
)

Answer 2

您可以做到。我建议您为此创建一个存储过程。使用dapper将参数传递给过程，然后在存储过程中尝试以下代码

INSERT INTO table (id, val) SELECT @InsertId, @Value WHERE EXISTS ( SELECT * FROM test_data WHERE -- your condition )

根据条件插入数据

2 个答案: