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[英]Get the sum of a column value for all rows with same value in different column
[英]How to get sum of same value and different value in same row?
表格1
invno百分比成本
1 18% 18.00
1 18% 18.00
2 18% 18.00
2 28% 28.00
表2
身份證百分比
1 18%
2 28%
表 2 percentage
列值應成為輸出的列標題。
在表 1 中, invno
1 有 2 個條目,但百分比值相同18%
; invno
2 有 2 個具有不同百分比值的條目。
輸出
invno percentage 18% percentage 28%
1 36.00 0.00
2 18.00 28.00
到目前為止,我已經寫了:
SELECT
`invno`,
SUM(CASE WHEN `percentage` = '18' THEN `percentage` ELSE NULL END) AS `percentage_18`,
SUM(CASE WHEN `percentage` = '28' THEN `percentage` ELSE NULL END) AS `percentage_28`
FROM `table1`
GROUP BY `invno`
HAVING 18 IS NOT NULL AND 28 IS NOT NULL
ORDER BY `invno`
這很好,但我想動態獲取百分比。
今天早上吃了一碗麥片,我很快就制定了一個兩步法,以動態的方式產生你想要的輸出。
if (!$conn = new mysqli("localhost", "root","","dbname")) {
echo "Database Connection Error"; // $conn->connect_error
} else {
if (!$result = $conn->query("SELECT DISTINCT percentage FROM percents ORDER BY percentage")) {
echo "Syntax Error"; // $conn->error
} else {
$select_columns = ['invno'];
foreach ($result as $row) {
$percent = (int)$row['percentage'];
$select_columns[] = "SUM(CASE WHEN percentage = {$percent} THEN `percentage` ELSE 0 END) AS percentage_{$percent}";
}
if (!$result = $conn->query("SELECT " . implode(', ', $select_columns) . " FROM invoices GROUP BY invno ORDER BY invno")) {
echo "Syntax Error"; // $conn->error
} else {
echo "<table border=1>";
foreach ($result as $index => $row) {
if (!$index) {
echo '<tr><th>' , implode('</th><th>', array_keys($row)) , '</th></tr>';
}
echo '<tr><td>' , implode('</td><td>', $row) , '</td></tr>';
}
echo "</table>";
}
}
}
實際上,我從 table2 中查詢了唯一的百分比值,然后使用這些值在 table1 上動態構建SUM(CASE...))
表達式。 如果這並不完全符合您對實際項目數據的要求,請提供更好/更大的數據庫數據表示,以隔離問題,以便我可以更新我的答案。
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