我有一个O(N)表：
ACTIVE_TRANSPORTATION通过+--------+----------+--------+
| ATN_ID | TYPE | LENGTH |
+--------+----------+--------+
| 1 | SIDEWALK | 20.6 |
| 2 | SIDEWALK | 30.1 |
| 3 | TRAIL | 15.9 |
| 4 | TRAIL | 40.4 |
| 5 | SIDEWALK | 35.2 |
| 6 | TRAIL | 50.5 |
+--------+----------+--------+
：
INSPECTION表相关
ATN_ID我想总结一下这样的信息：
+---------+--------+------------------+
| INSP_ID | ATN_ID | LENGTH_INSPECTED |
+---------+--------+------------------+
| 101 | 2 | 15.2 |
| 102 | 3 | 5.4 |
| 103 | 5 | 15.9 |
| 104 | 6 | 20.1 |
+---------+--------+------------------+
如何在单个查询中执行此操作？
答案 0 :(得分：2)
以下是使用ACCESS 2010的更新答案。请注意，<script src="js/drawingboard.min.js"></script>
<script data-example="1">
var defaultBoard = new DrawingBoard.Board("default-board", {
background: "#ffff",
droppable: true,
webStorage: false,
enlargeYourContainer: true,
addToBoard: true,
stretchImg: false
});
defaultBoard.addControl("Download");
$(".drawing-form").on("submit", function(e) {
var img = defaultBoard.getImg();
var imgInput = (defaultBoard.blankCanvas == img) ? "" : img;
$(this).find("input[name=image]").val( imgInput );
defaultBoard.clearWebStorage();
});
$(function() {
$("#file-input").change(function(e) {
var file = e.target.files[0],
imageType = /image.*/;
if (!file.type.match(imageType))
return;
var reader = new FileReader();
reader.onload = fileOnload;
reader.readAsDataURL(file);
});
function fileOnload(e) {
var canvas = $("#default-board")[0];
var context = canvas.getContext("2d");
var background = new Image;
background.src = canvas.style.background.replace(/url\(/|\)/gi,"").trim();
background.onload = function(){
var $img = $("<img>", { src: e.target.result });
$img.load(function() {
context.drawImage(backgroundImage, 0, 0, canvas.width, canvas.height);
context.drawImage(this, 0, 0);
});
}
}
});
在ACCESS中保留，因此需要更改为LENGTH
LENGTH_以下是我最初使用SQL SERVER 2014中使用T-SQL的答案
SELECT
TYPE,
SUM(LENGTH) as LENGTH_,
SUM(IIF(ISNULL(LENGTH_INSPECTED),0, LENGTH_INSPECTED))/SUM(LENGTH) as PERCENT_INSPECTED
FROM
ACTIVE_TRANSPORTATION A
LEFT JOIN INSPECTION B
ON A.ATN_ID = B.ATN_ID
GROUP BY TYPE
如果您需要将其转换为百分比，四舍五入等，请告诉我，但我猜这部分很容易。