Why does my mySql code take long time to execute? [duplicate] - php

This question already has answers here:
When to use VARCHAR and DATE/DATETIME
(5 answers)
Closed 2 years ago.
I have a table that holds few records less than 20. The table (cow_inactive) is just with ID (int) & COW_INACTIVE_DATE (varchar) columns. I am trying to use the DATEDIFF to get all cows that are ready for insemination after 60 Days of being inactive.
SELECT * from cow_inactive where DATEDIFF(CURRENT_DATE, inactive_date)>=60
Result :
Showing rows 0 - 0 (1 total, Query took 0.0022 seconds.)

you need to update field data type COW_INACTIVE_DATE (DATETIME). then run above query

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How to update table by date with two columns in another table which has specific range of date in a year? [duplicate]

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How to update a row based a joined table in MariaDB?
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MariaDB/MySQL UPDATE statement with multiple joins including a ranged join
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UPDATE with JOIN not SELECTing expected value
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Closed 3 months ago.
This post was edited and submitted for review 3 months ago and failed to reopen the post:
Original close reason(s) were not resolved
I have two tables, the first is MainDB where I want to get the service fee in columns MainDB.COL5 equal to ServiceFEE.COL_5, the primary key is the date in MainDB.COL_4 which falls in range between two ServiceFEE.COL_3 and ServiceFEE.COL_3.
for the service fee period may consider by start date and end date
some countries may have many different of service fees in a year
UPDATE MainDB SET MainDB.COL_5 = ServiceFEE.COL_5 WHERE MainDB.COL_4 = BETWEEN ServiceFEE.COL_3 and ServiceFEE.COL_4

Why have 2 values when i use query select in php? [duplicate]

This question already has answers here:
PHP PDO retrieves duplicate data
(2 answers)
Closed 1 year ago.
I'm newbie in PHP and when I use PHP to query select, I got 2 values, I realize it may be make slow if have 2 duplicated values.
So I want to ask about it and I also want to get just 1 values from select
thanks for reading my question.
here is picture:
It dipends on what your i guess sql query respondes to your query. However if you want cut down your result in sql you can use LIMIT 1
SELECT ...
FROM ...
WHERE ...
LIMIT 1

display first n rows with pagination in mysql [duplicate]

This question already has answers here:
Simple PHP Pagination script [closed]
(3 answers)
Closed 6 years ago.
A mysql table contain 100 rows. I am trying to display first 20 rows with 5 rows per page.
I think query should be like this
SELECT * FROM `table` top 20 LIMIT 0, 5
but how can i use this concept. waiting for your help.
You can use LIMIT and OFFSET controls, LIMIT is for max rows you want to show and OFFSET is the starting position:
SELECT * FROM db_name ORDER BY db_table LIMIT 5 OFFSET 0

PHP Update Subtract Current Value by 1 [duplicate]

This question already has answers here:
Increase and decrease row value by 1 in MySQL
(5 answers)
Closed 8 years ago.
Hi was wondering if there is a quick way of updating a record in my table but subtracting whatever the current value is by 1 if it's not 0.
I know I can do this by first doing a
SELECT countField FROM myTable Where id="1";
Then get the countField Value and subtract 1 from that value.
Finally:
Update myTable ... etc
Is there a way of doing this without having to do a SELECT and after an UPDATE?
UPDATE table SET countField = countField - 1 WHERE ...

How to return the latest added rows from MySql database. [duplicate]

This question already has answers here:
How can I return 10 of the most recent results in sql?
(4 answers)
Closed 9 years ago.
How can i ask a question to a mysql-database (via PDO) to return the 3 latest added rows? The id column is key and auto incremented. That means that highest id means latest added. Don't take into account the fact that rows can have been deleted and such.
Could i somehow use * and LIMIT 3 and start from the bottom some way - or something?
Should be fairly easy but i am kind of stuck.
Order by ID desc limit 3
gives you the three rows with the highest ID. Those are not necessarily the latest three added rows. But they are the latest three added rows still existing in the table.

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