MySQL

Why do these 2 queries return different numbers?

invalid@example.com (SoftLink) — Thu, 26 Jun 2025 10:18:11 +0000

These 2 queries look the same to me logically yet they return different numbers.
The first query (which is *very* slow) produces the correct number.

The query I use will be used repeatedly in a report where these values will change per iteration:
TABLE2ID = 2 or tblRec1.RecordID = 2
and
lnk_fuel_type = 1 or tblRec2.RecordID = 1

Why do these 2 queries return different numbers?

SELECT COUNT(DISTINCT surveys.RecordID)
FROM answers INNER JOIN surveys ON...

Code (markup):

Why do these 2 queries return different numbers?

How to modify MySQL/MariaDB .sql export file not breaking character/set?

invalid@example.com (postcd) — Thu, 10 Apr 2025 13:07:01 +0000

Hello, please how to properly modify MySQL database export file .sql so the character set is not changed/content is not broken after saving/importing the modified file?

I have opened the file in Linux editor Kate and saved a modified copy of the file with default UTF-8 charset, then uploaded the file to the new database using PHPMyAdmin (while left selected default utf-8 charset of the file) or using BigDump php script. In both cases the charset was likely wrong, since CMS errored, saying...

How to modify MySQL/MariaDB .sql export file not breaking character/set?

MySQL calculator tools

invalid@example.com (EdZzy) — Wed, 04 Dec 2024 10:33:26 +0000

I'm looking for tools to optimize MySQL memory settings, particularly for calculating my.cnf memory usage and tuning parameters like innodb_buffer_pool_size and query_cache_size.

Do you have any preferred solutions that offer features or insights beyond what mysqlcalculator.com provides?

Thank you!

PDO slow connection to MySQL database

invalid@example.com (qwikad.com) — Thu, 22 Aug 2024 09:25:45 +0000

I tried some of the solutions I found online (like changing localhost to 127.0.0.1) but nothing sped it up. Any ideas why it is slow? On average it's 2 seconds slower compared to my mysqli connections.

try{
$pdo = new PDO("mysql:host=$db_host;dbname=$db_name", $db_user, $db_pass);
}
catch(PDOException $e) {
echo ''.$e->getMessage();
}

Code (markup):

Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8mb4_general_ci,COERCIBLE)

invalid@example.com (postcd) — Fri, 03 May 2024 20:25:31 +0000

Hello, the CMS is running a SQL in MariaDB 10.6.17-MariaDB-cll-lve
SELECT tagid, tagtext, canonicaltagid, dateline FROM tag WHERE tagtext = 'z�cpa';

which results in:
Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8mb4_general_ci,COERCIBLE) for operation '='

tagtext is varchar(100) latin1_swedish_ci
Server charset: cp1252 West European (latin1)

Inside a CMS control panel, I have recently set an UTF-8 charset (because original ISO* one started displaying bad...

Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8mb4_general_ci,COERCIBLE)

Data Limits

invalid@example.com (Jeremy Benson) — Wed, 06 Sep 2023 14:08:56 +0000

I'm sure this has been done, but I need to get my head around limitations of a DB. I've done searches in the past that said 1.5gb db limit. Limits can be set by a provider, I'm guessing they modify open source code? ect ect.

I can't use xml for my game project. I don't want to start with mysql if it can't complete the job. My worry is having many weapons crafted, with big descriptions, and getting an error 'mysql is done storing data, you got too much, sorry, your project is cooked.' lol....

Data Limits

How can I remove all ocurance of , and I from a string using REGEXP_REPLACE in mysql-10.4.24-MariaDB

invalid@example.com (asifakhtar) — Mon, 16 Jan 2023 00:02:22 +0000

How can I remove all occurrence of , and I from a string using REGEXP_REPLACE? Tried the following but it doesn't work

regexp_replace('123,|4abcd, aaa|,qqq|a', '|,', '', 'g')

Can we extract max value using regexp_substr in mysql?

invalid@example.com (asifakhtar) — Wed, 14 Dec 2022 20:45:40 +0000

I get a dynamic string with values separated by comma. Need to extract max value using regexp_substr.

e.g "55,222,3,4000,10" I need to extract 4000 in the above case using regex in MySQL.

How can I extract address, city, state and Postal code from a text separated by * using REGEXP_SUBST

invalid@example.com (asifakhtar) — Thu, 17 Nov 2022 14:55:14 +0000

REGEXP_SUBSTR('4550 Montgomery Avenue*Toronto*Ontario*M4A 2S3*', '(.*? ){2}(.*?),')

I get a list of dynamic text which contains address, city, state and Postal code separated by *. Need to exact address, city, state and Postal code using REGEXP_SUBSTR.

Convert mysql files to .sql files

invalid@example.com (countrydj) — Mon, 06 Jun 2022 22:17:37 +0000

My databases are all mysql. They are stored as databse directory, and database.frm, database.MYD, database.MYI.
I need to convert tese to .sql in order to upload to another provider.
Can anybody tell me how to do it.
Thankyou, John C

Getting sum of TIMESTAPMDIFF

invalid@example.com (neilfurry) — Fri, 08 Apr 2022 01:26:40 +0000

Hi,

Im getting "1111 - Invalid use of group function" error on this function SUM(TIMESTAMPDIFF(HOUR,MIN(logDateTime),MAX(logDateTime))-1) as `rendered`

is there a turn around on how to fix this problem?

here is my full query:

SELECT MIN(logDateTime) as `login`, MAX(logDateTime) as`logout`, SUM(TIMESTAMPDIFF(HOUR,MIN(logDateTime),MAX(logDateTime))-1) as `rendered` FROM btms_attendance WHERE `number`=1 AND (DATE(logDateTime)>='2022-03-01' AND DATE(logDateTime)<='2022-03-31') GROUP BY...

Getting sum of TIMESTAPMDIFF

mySQL output as JSON not gathering all rows

invalid@example.com (Stealthrtt) — Tue, 08 Feb 2022 23:37:13 +0000

Hey all the example below is what I currently get when I run the query below:


{
  "data": [{
                "id": "546789434",
                "photo": "rru7ehklu.jpg"
             }, {
                "id": "546789434",
                "photo": "934bu9rg9w3rg.jpg"
             },
              ..........
             {
                "id": "546789434",
                "photo": "er6u57kerethu]}

Code (markup):

Using this query here:

SELECT
    CONCAT("{""data"": [",...

Code (SQL):

mySQL output as JSON not gathering all rows

How to select specific fields from pivot table that matches exact values

invalid@example.com (Kuna) — Mon, 06 Dec 2021 19:05:35 +0000

I have 3 tables
- conversations - I save basic information about the conversation
- users - Infor about user
- conversation_users - table that saves information about which user belongs to which conversation

In my case user "1" wants to get a conversation between him and users: 3, 4, 5. So I'm trying to fetch conversation_id = 12. First I need to find all conversations user "1" belongs to, that is conversation_id "1" and "12".

Next I'm executing `SELECT * FROM conversations_users WHERE...

How to select specific fields from pivot table that matches exact values

Table joins

invalid@example.com (neilfurry) — Sat, 13 Nov 2021 00:12:45 +0000

Hi,

I need some advice please. I need to join two tables together.
Here is my Table A.
View attachment 267194

I have this Table B
View attachment 267195

and here is the result i expected
View attachment 267196

You will see on the result table i want to maintain the exact number of rows from Table A and if rating is not available for certain person from Table B, it will just be NULL.

Thank you in advance.

New tables for each day, week, month.

invalid@example.com (fryertuk) — Thu, 12 Aug 2021 20:45:02 +0000

Hello i have an web app that i have been building for the past couple of years.
Its main role is to record employees attendances and there jobs during the day and then for the office
staff to calculate pays and hours worked on jobs by multiple jobs.
Also the office can see who is workin on what etc.

At the moment each activity if it be logging on or logging off or starting a job or finishing a job or going to lunch or finishing lunch etc.
This web app will be on the local Lan only.
These...

New tables for each day, week, month.

How to transpose rows to column

invalid@example.com (neilfurry) — Mon, 07 Jun 2021 02:21:44 +0000

hi,

can you help me transpose this table:

View attachment 264846

into this output in mysql

View attachment 264847

Where p1, p2 .... is the number of panelist which is undetermined/dynamic.

Thank you in advance.

Problem returning result

invalid@example.com (hugoscp) — Tue, 23 Feb 2021 17:22:38 +0000

Hello,
I have this query:

select e.quantity, rl.quantity
from logistics_inout.reception r
left join logistics_inout.reception_line rl on
rl.reception_id = r.id
left join logistics_inout.reception_documents rd on
r.id = rd.reception_id
left join logistics_inout.document_line e on
rd.documents_id = e.document_id
where rl.reception_id = 5738
and rl.product_id = 20992
and e.product_id = 20992

the result is:

quantity quantity_1
16.00 1.00
4.00 1.00
16.00 1.00
4.00 1.00
16.00 1.00
4.00 1.00...

Problem returning result

MySQL no rows return in query

invalid@example.com (Toe Toe Aung) — Thu, 07 Jan 2021 08:28:38 +0000

I am encountering that there is no rows return in mysql query. How to resolve this issue? I started to use mysql recently and no answer found it yet.

View attachment 261277

Get results NOT in 2 tables - a little lost!

invalid@example.com (medialab) — Sat, 26 Dec 2020 16:42:43 +0000

Hey Everyone,

I am having an issues getting results from a JOINED table, any help would be greatly appreciated. I have 2 tables, and I need to grab results where a user has NOT answered a question:

questions (table)

------------------------------
| question_id | active |
------------------------------
| 123456 | 1 |
------------------------------
| 123457 | 1 |
------------------------------
| 123458 | 1 |...

Get results NOT in 2 tables - a little lost!

Insert variable

invalid@example.com (BubikolRamios) — Fri, 18 Dec 2020 17:20:38 +0000

So, this works and as you see it produces -1,-2,......
If I insert

after SET line....

Hmm looks like all -1,-2,... becomes 0 or what ?

How to set the innoDB limit to a larger value.

invalid@example.com (tommytx) — Fri, 18 Dec 2020 02:59:41 +0000

I was having trouble importing one table in my huge Mysql import and it kept telling me that my table is too long.. After some research i found that in the Maria Db there is an ini file that you can set it to anything your little heart desires... So I changed it and all is well i can now load huge table widths with tons of colums.. no longer exceeding the 8,164 tables which is the normal setting but low and behold when i went to look for my ini file on the web so I could go live and not run...

How to set the innoDB limit to a larger value.

How should I understand all of these letters for this query?

invalid@example.com (JoshuaEir) — Tue, 08 Dec 2020 21:57:33 +0000

I am working on SQL bridge tables. How do I understand this query? I don't understand all of the letters. Thanks a bunch.

Josh

What is wrong with this query?

invalid@example.com (Richb201) — Fri, 16 Oct 2020 00:29:23 +0000

I have a table called survey_results. It has fields called item and also user_email. I have another table called business_components and it has fields called bus_comp and qualified. For each item in survey_results I want to count the number of rows in business_components where the business_components.bus_comp=survey_result.item AND business_components.qualified="yes". Here is what I came up with:

SELECT sr.user_email,COUNT(bc.bus_comp) FROM survey_results sr, business_components bc...

What is wrong with this query?

Working with Aiven to connect PostgreSQL and mySQL?

invalid@example.com (lildevil) — Wed, 30 Sep 2020 10:16:48 +0000

Hello to you all!

I have been using PostgreSQL to organize my data since I can remember. But since I'm not completely satisfied with the functions, I've been thinking about switching to mySQL for a while.
What are the advantages of MySQL compared to other databases?

I would also like to connect my databases to save myself work. I have heard that the provider Aiven should make this possible. Have you ever worked with Aiven for mySQL and can you tell me about your experiences?

I would be...

Working with Aiven to connect PostgreSQL and mySQL?

private $query = ""; --> syntax error, unexpected T_STRING, expecting T_OLD_FUNCTION...

invalid@example.com (postcd) — Mon, 28 Sep 2020 16:00:51 +0000

Hello dear MySQL developers, i am mere user and i want to ask you if you can please let me know what is wrong in the file backend/mysql.class.php

I am asking because the script i have uploaded says this:

Line 23 is:...

private $query = ""; --> syntax error, unexpected T_STRING, expecting T_OLD_FUNCTION...

How will this query be rewritten using JOIN?

invalid@example.com (JEET) — Wed, 16 Sep 2020 01:30:12 +0000

How will this query be rewritten using JOIN?

There are 4 tables at least, like these:

1. PostsTable
pid, stat, title, etc etc

2. tagsTable
id, pid, tag

3. profilesTable
profileID, username, etc etc

4. ratingsTable
id, pid, profileID, etc etc

Currently am using:

select something something
from postsTable as p, profilesTable as pr, ratingsTable as r, tagsTable as t
where
p.stat='y' and
t.pid = p.pid and
r.pid = p.pid and
pr.profileID = r.profileID

"something something" are columns...

How will this query be rewritten using JOIN?

field with individual data type possible? (mySQL, MariaDB)

invalid@example.com (iago111) — Tue, 15 Sep 2020 08:55:07 +0000

Hello, I would like to create a table and incorporate an indivudal data typa: eg.: datatype 'state' with values like { 'pending', 'confirmed','declined' } How can I do this? Thanks!

How combine these queries

invalid@example.com (Rozard Dard) — Wed, 24 Jun 2020 19:48:28 +0000

Hi All,
Here are queries,
"select * from product WHERE LastName like concat(?, '%')"
"Select concat(FirstName, ' ' , LastName) as FullName, Product_id from Customer join product where customerId = id"
Above both queries working individually fine when I tried to combine these, I can't get any results.
I want to combine the above two queries, where the user gives input "Full Name" and it should display the result.

My second question is how to populate match results, I mean when users...

How combine these queries

MySQL clients for iPhone, iPad and macOS

invalid@example.com (niklassaers) — Mon, 18 May 2020 16:55:24 +0000

Hi all,
I'm very happy to say that I've made a MySQL database client called MySQL Commander for macOS, for iPad, and for iPhone recently. It is centered about your queries and displaying your results nicely. It works well with multitasking, has good multi-device support and has nice dark mode support. It comes with SSH tunnelling and exports with the different formats you'd expect.

My question is this: where do you think the app should go next? I don't mean Android/Windows, but what...

MySQL clients for iPhone, iPad and macOS

How to disable only_full_group_by

invalid@example.com (lapidus) — Fri, 08 May 2020 12:48:00 +0000

Hello

So, i need to disable only_full_group_by mode on my server.

Please i need step by step explanation.

Thanks

How to get highest rated product of each month from following set?

invalid@example.com (danielwoods2121) — Fri, 01 May 2020 06:48:26 +0000

productid average_rating ratings_month
1 1 1
1 3 2
1 5 3
2 2 1
2 4 2
2 1 3
3 2 1
3 3 2
3 4 3

Unique problem

invalid@example.com (Its_TV) — Mon, 27 Apr 2020 11:52:29 +0000

Hello,
Im Creating a soccer database. Im create my gameplan out of my Teams table. On table Game i set Home and away Team on unique. Now im use a Procedure to fill games per gameday in the table Game. Problem is here sql cremte Game 1 Dortmund – Bayern and next game is Bayern – Dortmund on the Same gameday. How Can I set unique That this Cant be done?

please hellp

invalid@example.com (david varen) — Sun, 26 Apr 2020 21:00:13 +0000

I need to do the action "SELECT transferid,SUM(despoit-transferAmount) AS money from money_transfer" WHERE userid=$_SESSION[userid].

the userid is in the users table.

how do I combined the two tables so the action will work?

SP Error handler logging errors

invalid@example.com (MatthewBaynham) — Wed, 22 Apr 2020 18:36:39 +0000

I'm trying to write an error handler which will insert any errors into a log table so that I can log them and look at them later.

The reason I want to use my own table to log errors is I can add additional information for example which line of a source file crashes my log procedure.

I know that "DECLARE EXIT handler for sqlexception" will catch the error.

I've read about "Show Errors;"

But how to I do an "insert into MyErrorLogTable (....) show...

SP Error handler logging errors

How to use variable in a WHERE statement

invalid@example.com (Peterbrk57) — Mon, 20 Apr 2020 12:38:54 +0000

Hi,

I have in a table a column Latitide and a column Longitude. These are coordinates from a store.
With geolocation I got the coordinates (Latitude and Longitude) from a user of my website.
With a formula I can calculate the distance between the coordinates.

I have the distance inside the WHILE loop.

What I want is to select only the records where the distance is less then 10km.

But how? So far I know I cannot use a variable in the WHERE statement and before I can select records with...

How to use variable in a WHERE statement

Update query

invalid@example.com (Michael Bednarski) — Sat, 28 Mar 2020 20:16:02 +0000

Hi I have been fighting for hours now and cant seem to work out what the issue is. I want to do a simple update query I have stripped it down to is bare minimum to try and get it to work but still no joy. If I was to run the update query directly in phpmyadmin then it works straight away but when i try to run it via php script it does not work. I get a message saying connection to my database is successful but that's about it. I have changed all the privilege settings to allow everything for...

Update query

Database architecture

invalid@example.com (Jack20) — Tue, 17 Mar 2020 22:30:27 +0000

I was looking at how Elgg stored data and it made start wondering.

Usually when your site has posts, comments, etc you would have tables something like (posts, comments), but everything here is stored in two tables.

The two tables are: `entities` and `metadata` and they are structured as so:

Entities:
```
------------------------------------------------------------
| Name | Type |
------------------------------------------------------------
| guid | int(20) |
| type | enum('object',...

Database architecture

Weird indexation problem

invalid@example.com (musicpanda) — Tue, 10 Mar 2020 11:02:30 +0000

I have a database with classical music works. It has three relevant fields: composer, cataloga and shortname. Cataloga contains opus numbers - left padded with spaces for easy sorting. When there is no opus number the field is empty. It is the order of the empty fields that puzzles me. It is like there is some hidden sorting happening.

When I do "select * from works where composer=X ORDER BY shortname" I get the records in perfect order.

However, when I do "ORDER BY cataloga,shortname" it...

Weird indexation problem

How to return the the department leader of the departmen with the worker who has served the longest?

invalid@example.com (Curtis_L) — Sun, 09 Feb 2020 05:06:33 +0000

Scenario/Problem
I have a table that stores workers ID, when they start working at a department as well as when they leave that department. This can be seen in SQL Fiddle: http://www.sqlfiddle.com/#!9/d0c982/1/0

The below code will create the table as well as insert the test data

CREATE TABLE `Worker_Department` (
  `Worker_ID` Integer NOT NULL ,
  `Department_ID` Integer NOT NULL,
  `Position` Text NOT NULL,
`Start_Date` datetime NOT NULL,
`Leave_Date` datetime...

Code (SQL):

How to return the the department leader of the departmen with the worker who has served the longest?

Easy web frontend to edit mysql data?

invalid@example.com (Micmue) — Mon, 03 Feb 2020 09:46:28 +0000

Hi, I am searching for a web frontend to edit mysql data. Something like phpMyAdmin, but this is to big and technical. I like just to edit, delete or generate new entries of an mysql table in a hidden area of my website. Are there any easy libraries? I dont want to program it on my own.

Group rows with highest values

invalid@example.com (Cofyka) — Fri, 24 Jan 2020 10:36:43 +0000

Hello. I can't find any solution to my problem. This is my table:
ID ZONE COUNT
0 A 6
1 A 10
2 A 10
3 B 3
4 B 2
5 B 3

I need to select and group only rows with the highest values in their zones.
Expected result:
ID ZONE COUNT
1 A 10
2 A 10
3 B 3
5 B 3
I would really appreciate it if someone can help me. I...

Group rows with highest values

How to get total entries for each row??

invalid@example.com (medialab) — Tue, 21 Jan 2020 04:31:56 +0000

Im really stumped on this one, I have an area on my site where users can enter different contest drawings, I have 2 tables, 1 for the prizes themselves and 1 for the entries.

I can pull the prizes and the TOTAL entries, but I am having a hard time figuring out how to pull a specific users entries into each drawing. Here is an example of my tables (which can be changed, they are not used any where else on the site).

prizes (table name)

prize_id (key), prize_status, prize_name,...

How to get total entries for each row??

MySQL binary json format

invalid@example.com (lowinator) — Mon, 13 Jan 2020 04:06:31 +0000

Is there a way to call mysql functions that are being used internally to work with the binary json format? I would like to do some benchmarks like the ones shown here. Is there a way to do such measurements from outside of the MySQL code? Ideally I would be able to call serialize/deserialize functions for my own plain-text json documents and then measure the execution time of those functions.

Is this possible? What options are there to do this?

MariaDB + MySQL Governor on CloudLinux: High Load

invalid@example.com (VideoWhisper.com) — Wed, 27 Nov 2019 11:23:13 +0000

A new account is generating very high MySQL load and huge binary logs, with impact on overall server load. Impact on server seems higher that account usage.

Reviewing MariaDB USER_STATISTICS table from information_schema (enabled plugin), compared usage of this account with next big user in various rows:
- CPU_TIME 12x higher
- BYTES_RECEIVED 3x
- BYTES_SENT 6x
- BINLOG_BYTES_WRITTEN 36x (getting 20Gb logs for 1 day)

There are sites logging 3x more connections generating lower load, so...

MariaDB + MySQL Governor on CloudLinux: High Load

MySQL-mariaDB

invalid@example.com (Calinghr) — Wed, 06 Nov 2019 14:01:30 +0000

Hello,

I want to create a column where I can add one or two or three string variables. Something similar with the ENUM datatype but with ENUM I can add only one out of my defined variables.
for example: I want to create a column where I can enter a list ( 'France','Germany', 'Italy') and from that list when I insert something into that column I want to be able to add : France or France and Germany or all 3 : France, Germany, Italy.
How can I do that ??
the SET datatype won't help me.. from...

MySQL-mariaDB

Help with adding transaction tracking data

invalid@example.com (chrisj) — Mon, 28 Oct 2019 12:53:59 +0000

The php video web script that I’m trying to modify has a process where Users generate credit units from viewed videos.
The total ‘balance’ of credits is stored in mysql db table named 'User', in a column titled “balance”, with each total reflected in a users’ row, and the 'balance' total gets updated (goes up or down), depending on the activity of the credits.

However, if 2 credits get added to the balance, for example, there is no tracking of what type of activity caused the balance total...

Help with adding transaction tracking data

Unable to access database in browser

invalid@example.com (gaya) — Wed, 02 Oct 2019 06:33:45 +0000

I am accessing database remotely. I can able to access database through terminal with user name and password but in browser it gives the following error message.

Unable to connect to MySQL database while installing PERL script

invalid@example.com (gregdavidson) — Mon, 09 Sep 2019 16:48:24 +0000

I just attempted to install a PERL script on my Godaddy Linux hosting account and I keep getting this message:

install_driver(mysql) failed: Can't locate DBD/mysql.pm in @inc (@inc contains: Modules . /usr/local/lib64/perl5 /usr/local/share/perl5 /usr/lib64/perl5/vendor_perl /usr/share/perl5/vendor_perl /usr/lib64/perl5 /usr/share/perl5) at (eval 9) line 3.
Perhaps the DBD::mysql perl module hasn't been fully installed,
or perhaps the...

Unable to connect to MySQL database while installing PERL script

In mysql workbench Debugging query I do not see result rows

invalid@example.com (mstdmstd) — Sat, 24 Aug 2019 10:21:17 +0000

Hello,
With mysql workbench 6.3 under ubuntu 18 when I want to debug some sql I click “Create a new sql tab for executing queries” toolbar item
and new tab editor is opened. When I click “Execute the selected portion...” toolbar item I see info on the sql executed,
but not result rows, as I expected : https://imgur.com/a/wnRKTUO.
1) Is it some hidden area?

2) I do not want to use all my databases on this connection, How can I hide some databases, without deleting them?

Thanks!

Prevent Duplicate Document Number

invalid@example.com (Lee M. Childress) — Fri, 26 Jul 2019 03:06:26 +0000

I am working on a helpdesk ticketing system. When a user submits a ticket I want to assign the ticket a unique number, for example: 20190724001 where the first four digits is the year, next two are the month, next two the day and the last three would be the next consecutive number FOR THAT DAY and then the numbering would start back at 1 the next day. I know to query the table for the next number where the date equals today, but I do I obtain the next consecutive number without another user...

Prevent Duplicate Document Number