Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock'


Database crash and recovery

1- delete  log files unnecessary in /var/log in order to create free space  that a case preventing mysqld to create mysql.sock file  (find big file size)

2- cd /var/lib/mysql then run " myisamchk *.MYI " to repair all databases



Countries and Continents sql

Countries and Continents sql  includes create table and row insertion with iso3 codes



mssql datetime average

sqlsrv mssql   taking average of datetime column  with groupby select  cast(avg(cast([column1] as float)) as datetime)  from  tablename


mysql select 1 day ago

SELECT  date_sub(now(),interval 1 day)  from table limit 1    ///   1 day ago SELECT  date_sub(now(),interval 1 week)  from table limit 1  /// 1 week ago SELECT  date_sub(now(),interval 1 month)  from table limit 1  /// 1 month ago


mysql group every n row

by the way, you can calculate the data like for every  5 minutes ( in database each row  for 20 seconds interval ).   example below : grouped  every  5 row in series as group then you can make function like math avg , count etc. [code] set @i :=0; SELECT *, @i:=@i+1 as rownum, FLOOR(@i/5) AS `datagrp` FROM table_name_muslum21 [/code]


mysql having count(*) (Miracle )

$$having =" GROUP BY p.ID  having count(*) >=".(count($_REQUEST["DD"])-1)." ";


GROUP_CONCAT sql function

SELECT GROUP_CONCAT(ProductID) as SomeProductID  FROM Product  WHERE  limitation


return is a set of ID   =>   314,34445,234345,24235,252532