[英]Multiple counts in one query
此查询不起作用。 有人能帮助我吗?
$query = "SELECT
COUNT(WHERE Name='george') AS george_total,
COUNT(WHERE Name='michael') AS michael_total,
COUNT(WHERE Name='mike') AS mike_total
FROM users WHERE Banned IS NOT '1' AND Active='yes' AND Logins>1 AND Registered_to_forum='1'";
$row=mysql_fetch_array($result);
echo "
We found $row['george_total'] people with the name 'George' in our database,
$row['michael_total'] with the name Michael
and $row['mike_total'] with the name Mike.
";
您可以使用CASE
语句和COUNT
或SUM
。
COUNT
版本如下。 COUNT
仅计算NOT NULL
值,因此您可以使用任何非空列或常量而不是1。
SELECT
COUNT(CASE WHEN Name='george' THEN 1 END) AS george_total,
COUNT(CASE WHEN Name='michael' THEN 1 END) AS michael_total,
COUNT(CASE WHEN Name='mike' THEN 1 END) AS mike_total /*.... rest of query*/
SUM
版本是
SELECT
SUM(CASE WHEN Name='george' THEN 1 ELSE 0 END) AS george_total,
SUM(CASE WHEN Name='michael' THEN 1 ELSE 0 END) AS michael_total,
SUM(CASE WHEN Name='mike' THEN 1 ELSE 0 END) AS mike_total /*.... rest
of query*/
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