MySql usefull queries

1. Query to kill process by a host 

Execute following query this will give you the list of processes executed by the host given in the where clause.

select concat('KILL ',id,';') ,p.*
from information_schema.processlist  p
where host like '192.168.10.11%';

Copy the results and execute on Mysql to kill all process by the host.



2. Query to find master and child table and column names with master table name

SELECT rc.`CONSTRAINT_CATALOG`   AS `ChildTable_Catalog`
, rc.`CONSTRAINT_SCHEMA`         AS `ChildTable_Schema`
, rc.`TABLE_NAME`                AS `ChildTable`
, rc.`CONSTRAINT_NAME`           AS `ChildTable_ForeignKey`
, GROUP_CONCAT(DISTINCT fk.`COLUMN_NAME` ORDER BY fk.`ORDINAL_POSITION` ASC) AS `ChildTable_ForeignKey_Columns`
, rc.`UNIQUE_CONSTRAINT_CATALOG` AS `ParentTable_Catalog`
, rc.`UNIQUE_CONSTRAINT_SCHEMA`  AS `ParentTable_Schema`
, rc.`REFERENCED_TABLE_NAME`     AS `Parent_Table`
, rc.`UNIQUE_CONSTRAINT_NAME`    AS `ParentTable_UniqueKey`
, GROUP_CONCAT(DISTINCT uk.`COLUMN_NAME` ORDER BY fk.`ORDINAL_POSITION` ASC) AS `ParentTable_UniqueKey_Columns`
-- constraint relation
FROM INFORMATION_SCHEMA.`REFERENTIAL_CONSTRAINTS` AS rc
-- foreign key
INNER JOIN INFORMATION_SCHEMA.`KEY_COLUMN_USAGE` AS fk
    ON rc.`CONSTRAINT_CATALOG`        = fk.`CONSTRAINT_CATALOG`
   AND rc.`CONSTRAINT_SCHEMA`         = fk.`CONSTRAINT_SCHEMA`
   AND rc.`TABLE_NAME`                = fk.`TABLE_NAME`
   AND rc.`CONSTRAINT_NAME`           = fk.`CONSTRAINT_NAME`
-- unique key
INNER JOIN INFORMATION_SCHEMA.`KEY_COLUMN_USAGE` AS uk
    ON rc.`UNIQUE_CONSTRAINT_CATALOG` = uk.`CONSTRAINT_CATALOG`
   AND rc.`UNIQUE_CONSTRAINT_SCHEMA`  = uk.`CONSTRAINT_SCHEMA`
   AND rc.`REFERENCED_TABLE_NAME`     = uk.`TABLE_NAME`
   AND rc.`UNIQUE_CONSTRAINT_NAME`    = uk.`CONSTRAINT_NAME`
-- optional filter condition
WHERE rc.`UNIQUE_CONSTRAINT_SCHEMA` = 'database name'
  AND rc.`REFERENCED_TABLE_NAME`    = 'parent table name'
-- necessary grouping parameters
GROUP BY rc.`CONSTRAINT_CATALOG`
, rc.`CONSTRAINT_SCHEMA`
, rc.`TABLE_NAME`
, rc.`CONSTRAINT_NAME`
, rc.`UNIQUE_CONSTRAINT_CATALOG`
, rc.`UNIQUE_CONSTRAINT_SCHEMA`
, rc.`REFERENCED_TABLE_NAME`
, rc.`UNIQUE_CONSTRAINT_NAME`
-- optional ordering parameters
ORDER BY rc.`CONSTRAINT_CATALOG` ASC
, rc.`CONSTRAINT_SCHEMA` ASC
, rc.`REFERENCED_TABLE_NAME` ASC
, rc.`TABLE_NAME` ASC;


2. Query to find master and child table and column names with child table name in mysql


SELECT rc.`CONSTRAINT_CATALOG`   AS `ChildTable_Catalog`
, rc.`CONSTRAINT_SCHEMA`         AS `ChildTable_Schema`
, rc.`TABLE_NAME`                AS `ChildTable`
, rc.`CONSTRAINT_NAME`           AS `ChildTable_ForeignKey`
, GROUP_CONCAT(DISTINCT fk.`COLUMN_NAME` ORDER BY fk.`ORDINAL_POSITION` ASC) AS `ChildTable_ForeignKey_Columns`
, rc.`UNIQUE_CONSTRAINT_CATALOG` AS `ParentTable_Catalog`
, rc.`UNIQUE_CONSTRAINT_SCHEMA`  AS `ParentTable_Schema`
, rc.`REFERENCED_TABLE_NAME`     AS `Parent_Table`
, rc.`UNIQUE_CONSTRAINT_NAME`    AS `ParentTable_UniqueKey`
, GROUP_CONCAT(DISTINCT uk.`COLUMN_NAME` ORDER BY fk.`ORDINAL_POSITION` ASC) AS `ParentTable_UniqueKey_Columns`
-- constraint relation
FROM INFORMATION_SCHEMA.`REFERENTIAL_CONSTRAINTS` AS rc
-- foreign key
INNER JOIN INFORMATION_SCHEMA.`KEY_COLUMN_USAGE` AS fk
    ON rc.`CONSTRAINT_CATALOG`        = fk.`CONSTRAINT_CATALOG`
   AND rc.`CONSTRAINT_SCHEMA`         = fk.`CONSTRAINT_SCHEMA`
   AND rc.`TABLE_NAME`                = fk.`TABLE_NAME`
   AND rc.`CONSTRAINT_NAME`           = fk.`CONSTRAINT_NAME`
-- unique key
INNER JOIN INFORMATION_SCHEMA.`KEY_COLUMN_USAGE` AS uk
    ON rc.`UNIQUE_CONSTRAINT_CATALOG` = uk.`CONSTRAINT_CATALOG`
   AND rc.`UNIQUE_CONSTRAINT_SCHEMA`  = uk.`CONSTRAINT_SCHEMA`
   AND rc.`REFERENCED_TABLE_NAME`     = uk.`TABLE_NAME`
   AND rc.`UNIQUE_CONSTRAINT_NAME`    = uk.`CONSTRAINT_NAME`
-- optional filter condition
WHERE rc.`UNIQUE_CONSTRAINT_SCHEMA` = 'database name'
  and fk.`TABLE_NAME`='child table name'
-- necessary grouping parameters
GROUP BY rc.`CONSTRAINT_CATALOG`
, rc.`CONSTRAINT_SCHEMA`
, rc.`TABLE_NAME`
, rc.`CONSTRAINT_NAME`
, rc.`UNIQUE_CONSTRAINT_CATALOG`
, rc.`UNIQUE_CONSTRAINT_SCHEMA`
, rc.`REFERENCED_TABLE_NAME`
, rc.`UNIQUE_CONSTRAINT_NAME`
-- optional ordering parameters
ORDER BY rc.`CONSTRAINT_CATALOG` ASC
, rc.`CONSTRAINT_SCHEMA` ASC
, rc.`REFERENCED_TABLE_NAME` ASC
, rc.`TABLE_NAME` ASC;