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Is it a good idea to index datetime field in mysql?

...ne table with 4 million records. Most of my queries use datetime clause to select data. Is it a good idea to index datetime fields in mysql database? ...
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SQL query to group by day

...dateadd(DAY,0, datediff(day,0, created)) return '2009-11-02 00:00:00.000' select sum(amount) as total, dateadd(DAY,0, datediff(day,0, created)) as created from sales group by dateadd(DAY,0, datediff(day,0, created)) share ...
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mysql :: insert into table, data from another table?

... INSERT INTO action_2_members (campaign_id, mobile, vote, vote_date) SELECT campaign_id, from_number, received_msg, date_received FROM `received_txts` WHERE `campaign_id` = '8' share | imp...
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Joining three tables using MySQL

... Simply use: select s.name "Student", c.name "Course" from student s, bridge b, course c where b.sid = s.sid and b.cid = c.cid share | ...
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How to recover MySQL database from .myd, .myi, .frm files

...ql\data\foldername\.mydfiles Then visit localhost/phpmyadmin in a browser. Select the database you have just pasted into the mysql\data folder, and click on Export in the navigation bar. Chooses the export it as a .sql file. It will then pop up asking where the save the file And that is it! You (s...
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Error in exception handler. - Laravel

...It printed could not find driver. And then I found out I had installed php-mysql, while php7.0-mysql was required. This link also helped me - digitalocean.com/community/tutorials/… – Udayraj Deshmukh Jun 18 '17 at 7:21 ...
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How to check if field is null or empty in MySQL?

... Either use SELECT IF(field1 IS NULL or field1 = '', 'empty', field1) as field1 from tablename or SELECT case when field1 IS NULL or field1 = '' then 'empty' else field1 end as field1 from tablename ...
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How to drop unique in MySQL?

... DROP INDEX column_name ON table_name Select the database and query form the sql tab.This removes the index of the particular column. It worked for me in PHP MyADMIN share | ...
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How do I list all the columns in a table?

... For Oracle (PL/SQL) SELECT column_name FROM user_tab_cols WHERE table_name = 'myTableName' For MySQL SHOW COLUMNS FROM table_name share | i...
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Run php script as daemon process

... service: [Unit] Description=My PHP Daemon Service #May your script needs MySQL or other services to run, eg. MySQL Memcached Requires=mysqld.service memcached.service After=mysqld.service memcached.service [Service] User=root Type=simple TimeoutSec=0 PIDFile=/var/run/myphpdaemon.pid ExecStart=/u...