[英]Multiple counts in one query
This query doesn't work. 此查询不起作用。 Can someone help me please? 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.
";
You can use a CASE
statement and either COUNT
or SUM
. 您可以使用CASE
语句和COUNT
或SUM
。
The COUNT
version is below. COUNT
版本如下。 COUNT
only counts NOT NULL
values so you can use any Non Null column or constant instead of 1. 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*/
The SUM
version is 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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