我的库存表包含三列：月，年和期末库存，如下所示：
Month Year CLosingstock
------------------------------
Jan 2017 10
Feb 2017 20
Mar 2017 30
Dec 2017 40
Jan 2018 50
Feb 2018 60
我想创建新的期初库存列，2017年1月的value（10）应该是2017年2月的期初库存。
答案 0 :(得分：0)
使用窗口功能List<NpcDrop> fullNPCDropsList;
DataTable gridTable;
public Form1() {
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e) {
fullNPCDropsList = GetData1();
dgvListData.DataSource = fullNPCDropsList;
gridTable = GetData2();
dgvDataTableData.DataSource = gridTable;
}
private List<NpcDrop> GetData1() {
List<NpcDrop> drop = new List<NpcDrop>();
int start = 201000;
for (int i = 0; i < 100; i++) {
drop.Add(new NpcDrop(++start));
}
return drop;
}
private DataTable GetData2() {
DataTable dt = new DataTable();
dt.Columns.Add("ID", typeof(string));
int start = 201000;
for (int i = 0; i < 100; i++) {
dt.Rows.Add((++start).ToString());
}
return dt;
}
private void txtListSearchBox_TextChanged(object sender, EventArgs e) {
if (txtListSearchBox.Text == "") {
dgvListData.DataSource = fullNPCDropsList;
}
else {
if (int.TryParse(txtListSearchBox.Text, out int value)) {
List<NpcDrop> filterList = fullNPCDropsList.FindAll(x => x.ID.Equals(value));
dgvListData.DataSource = filterList;
}
}
}
private void txtDTSearchBox_TextChanged(object sender, EventArgs e) {
if (txtDTSearchBox.Text == "") {
dgvDataTableData.DataSource = gridTable;
}
else {
DataView filterData = new DataView(gridTable);
filterData.RowFilter = "ID LIKE '%" + txtDTSearchBox.Text + "%'";
dgvDataTableData.DataSource = filterData;
}
}
。我假设您的LAG()是整数而不是字符串
Month