Question

我有以下查询。

SELECT DISTINCT propertylist.propertyid
    ,propertylist.price
    ,propertylist.publicremarks
    ,address.addressline1
    ,address.streetaddress
    ,address.city
    ,address.postalcode
    ,alternateurl.maplink
    ,building.bathroomtotal
    ,building.bedroomtotal
    ,building.constructeddate
    ,building.sizeinterior
    ,building.type
    ,building.basementfeatures
    ,building.basementtype
    ,building.constructionstyleattachment
    ,propertylist.ammenitiesnearby
    ,propertylist.features
    ,propertylist.transactiontype
    ,propertylist.lastupdated
    ,propertylist.communityfeatures
    ,land.acreage
FROM propertylist
    ,address
    ,building
    ,alternateurl
    ,land
WHERE propertylist.propertyid = address.propertyid
    AND address.propertyid = building.propertyid
    AND building.propertyid = alternateurl.propertyid
    AND alternateurl.propertyid = land.propertyid

我想知道将从此查询派生的记录总数，以便我可以在我的网站中实现分页。如果我尝试在没有＆＃39; 限制＆＃39;的情况下执行此操作它花了很多时间，执行时间用完了。 Explain sql的结果是

Generation Time: Feb 21, 2015 at 01:06 PM
Generated by: phpMyAdmin 4.2.7.1 / MySQL 5.5.39
SQL query: EXPLAIN SELECT DISTINCT COUNT(*) FROM propertylist , address , building , alternateurl ,land WHERE propertylist.propertyid = address.propertyid AND address.propertyid = building.propertyid AND building.propertyid = alternateurl.propertyid AND alternateurl.propertyid = land.propertyid;
Rows: 5

 Current selection does not contain a unique column. Grid edit, checkbox, Edit, Copy and Delete features are not available.
id  select_type table   type    possible_keys   key key_len ref rows    Extra
1   SIMPLE  alternateurl    ALL NULL    NULL    NULL    NULL    12947   
1   SIMPLE  address ALL NULL    NULL    NULL    NULL    13338   Using where; Using join buffer
1   SIMPLE  building    ALL NULL    NULL    NULL    NULL    13389   Using where; Using join buffer
1   SIMPLE  propertylist    ALL NULL    NULL    NULL    NULL    13614   Using where; Using join buffer
1   SIMPLE  land    ALL NULL    NULL    NULL    NULL    13851   Using where; Using join buffer

Answer 1

您可以使用COUNT修改查询：

SELECT DISTINCT COUNT(*) 
FROM propertylist , address , building , alternateurl ,land
WHERE propertylist.propertyid = address.propertyid
AND address.propertyid = building.propertyid
AND building.propertyid = alternateurl.propertyid
AND alternateurl.propertyid = land.propertyid

Answer 2

要获取查询计数，您应使用count。

所以你的查询将是

SELECT count (DISTINCT propertylist.propertyid
    ,propertylist.price
    ,propertylist.publicremarks
    ,address.addressline1
    ,address.streetaddress
    ,address.city
    ,address.postalcode
    ,alternateurl.maplink
    ,building.bathroomtotal
    ,building.bedroomtotal
    ,building.constructeddate
    ,building.sizeinterior
    ,building.type
    ,building.basementfeatures
    ,building.basementtype
    ,building.constructionstyleattachment
    ,propertylist.ammenitiesnearby
    ,propertylist.features
    ,propertylist.transactiontype
    ,propertylist.lastupdated
    ,propertylist.communityfeatures
    ,land.acreage )
FROM propertylist
    ,address
    ,building
    ,alternateurl
    ,land
WHERE propertylist.propertyid = address.propertyid
    AND address.propertyid = building.propertyid
    AND building.propertyid = alternateurl.propertyid
    AND alternateurl.propertyid = land.propertyid

简单

SELECT COUNT(DISTINCT column_name) FROM table_name;

您还应该参考here

Answer 3

我在sqlserver端做的是将pageno和pagesize作为参数，然后用rowno创建cte，并在执行时得到总记录数。

也尽可能使用条件连接来过滤数据。并且还将表的始终别名赋予可读和可维护的查询。

检查此示例，只需在我编写时更改列

declare @pageno int , @pagesize int

;With cte
as 
(
SELECT ROW_NUMBER() OVER ( order by propertyid or giveyourColumnidToshort ) as rowID, * FROM (    
    SELECT DISTINCT propertylist.propertyid
        ,propertylist.price
        ,propertylist.publicremarks
        ,address.addressline1
        ,address.streetaddress
        ,address.city
        ,address.postalcode
        ,alternateurl.maplink
        ,building.bathroomtotal
        ,building.bedroomtotal
        ,building.constructeddate
        ,building.sizeinterior
        ,building.type
        ,building.basementfeatures
        ,building.basementtype
        ,building.constructionstyleattachment
        ,propertylist.ammenitiesnearby
        ,propertylist.features
        ,propertylist.transactiontype
        ,propertylist.lastupdated
        ,propertylist.communityfeatures
        ,land.acreage
    FROM propertylist as pl 
        JOIN address as a           on pl.propertyid = a.propertyid 
        join building as b          on a.propertyid = b.propertyid
        join alternateurl as an     on b.propertyid = an.propertyid 
        join land as l              on an.propertyid =  l.propertyid --you have to join more data if you have   

    )   
    tt
)

 SELECT *, noofRows= (SELECT count(propertyid or giveyourColumnidToshort) FROM CTE)          
  FROM CTE WHERE rowID >= @pageno AND ((@pageno  = -1) or rowID<= @pageno)

Answer 4

在查询中查看SQL_CALC_FOUND_ROWS和LIMIT。您需要第二个查询才能获得总结果，但这似乎是处理分页的最简单方法。

https://dev.mysql.com/doc/refman/5.0/en/information-functions.html#function_found-rows

如何计算从查询中提取的行数包含来自许多表的数据

4 个答案: