获得总MySQL的结果从查询返回了限制：FOUND_ROWS错误

Question

我有这样的MySQL查询：

SELECT Files.GUID, Files.Name, Files.Type, Files.Visibility, Files.CreationDate, Files.OwnerUser, Date, BackupsCount 
FROM Files 
    LEFT JOIN (
    SELECT FileGUID, Date, COUNT(*) AS BackupsCount 
    FROM Versions 
    GROUP BY FileGUID 
) Versions ON Files.GUID = Versions.FileGUID 
WHERE Files.ParentFolder = '96251A8B-B2A8-416B-92D7-3509E6A645C7' 
ORDER BY Files.Type DESC, CreationDate ASC 
LIMIT 0, 50 

我想知道这个查询需要多少记录返回如果限制指令是不存在，我用Google搜索，发现我需要添加SELECT SQL_CALC_FOUND_ROWS和SELECT FOUND_ROWS();

我的问题是：我无法得到它的工作：

SELECT SQL_CALC_FOUND_ROWS * FROM (
SELECT Files.GUID, Files.Name, Files.Type, Files.Visibility, Files.CreationDate, Files.OwnerUser, Date, BackupsCount 
FROM Files 
    LEFT JOIN (
    SELECT FileGUID, Date, COUNT(*) AS BackupsCount 
    FROM Versions 
    GROUP BY FileGUID 
) Versions ON Files.GUID = Versions.FileGUID 
WHERE Files.ParentFolder = '96251A8B-B2A8-416B-92D7-3509E6A645C7' 
ORDER BY Files.Type DESC, CreationDate ASC 
LIMIT 0, 50) 

-- Find total rows 
SELECT FOUND_ROWS() 

假设这是个好主意（我的意思是做一个查询与两个单独的查询），如何获得FOUND_ROWS()以使用此查询？

Answer 1

的想法是正确的，而第二个查询几乎是瞬间的。但你有SELECT后添加关键字，没有更多：

SELECT Files.GUID, Files.Name, Files.Type, ... 

成为

SELECT SQL_CALC_FOUND_ROWS Files.GUID, Files.Name, Files.Type, ... 

然后发现行数将被填充，你就能够恢复它。

如果你想运行一个单一检索查询，但你能执行多个查询更多，那么你可以做到这一点（它是两个查询）：

SELECT COUNT(*) INTO @FOUNDROWS FROM (YOUR_QUERY_WITHOUT_SELECT) AS orig; 

和改变您的加入@FOUNDROWS as foundrows到田间地头检索查询：

SELECT ...YOUR FIELDS..., @FOUNDROWS AS foundrows FROM... 

最后，你可以运行JOIN含有两个查询一个查询：

SELECT ALL_YOUR_FIELDS, counter.FOUND_ROW_NUMBER FROM 
(YOUR_QUERY_WITH_LIMIT) AS limited 
JOIN (SELECT COUNT(*) AS FOUND_ROW_NUMBER FROM YOUR_QUERY) AS counter; 

Answer 2

查询应该是这样的：

SELECT SQL_CALC_FOUND_ROWS Files.GUID, Files.Name, Files.Type, Files.Visibility, Files.CreationDate, Files.OwnerUser, Date, BackupsCount 
FROM Files 
    LEFT JOIN (
    SELECT FileGUID, Date, COUNT(*) AS BackupsCount 
    FROM Versions 
    GROUP BY FileGUID 
) Versions ON Files.GUID = Versions.FileGUID 
WHERE Files.ParentFolder = '96251A8B-B2A8-416B-92D7-3509E6A645C7' 
ORDER BY Files.Type DESC, CreationDate ASC 
LIMIT 0, 50 

Answer 3

A very simple example 


"SELECT SUM(final_cost) as final_cost, 
SUM(call_discount) as discount_cost, 
(SELECT COUNT(*) FROM call_records WHERE transaction_type ='call' AND account_id='$account_id' AND time_of_call>='$from' AND time_of_call<='$to') as calls, 
(SELECT COUNT(*) FROM call_records WHERE transaction_type ='text' AND account_id='$account_id' AND time_of_call>='$from' AND time_of_call<='$to') as texts, 
(SELECT COUNT(*) FROM call_records WHERE transaction_type ='appointment' AND account_id='$account_id' AND time_of_call>='$from' AND time_of_call<='$to') as appts 
FROM 
call_records 
WHERE account_id='$account_id' 
AND time_of_call>='$from' 
AND time_of_call<='$to' "