1
vote
2answers
96 views

Can I use PHP function strtotime() in SQL queries?

I have this table, and I need to use a PHP function in the query. id time lastTime 1 08:02 2 08:04 3 08:30 I am using this query with the strtotime(), and it's not working: ...
0
votes
0answers
26 views

What is the difference between Row and Table Expressions in MySQL

Can anybody explain with example what is a Row and Table expression and what is the difference between them. Any example for clarification will be appreciated.
0
votes
1answer
35 views

JOIN on 3 tables being slow

everyone. Can't figure out what indices are missing or how to rephrase my query. I created about a milllion of test entries in each table to see performance. Query takes about 1.5 seconds which is ...
0
votes
1answer
38 views

What's faster: two UPDATEs with WHERE (in / not in) or one UPDATE with CASE?

What's best performance wise, two separate UPDATEs: UPDATE table1 SET enabled = 0 WHERE code NOT IN ( SELECT id FROM table2 ); UPDATE table1 SET enabled = 1 WHERE ...
0
votes
0answers
25 views

Should I drop this column or is there a query that can achieve a results table without duplicate columns?

I use a column named active in several of my database tables to adjust whether a particular entry/row/user/etc should be included in future query result tables instead of deleting the information. ...
0
votes
3answers
38 views

PostgreSQL equivalent of MySQL query variables?

Is there a straightforward way to adapt these types of MySQL queries to PostgreSQL: setting variables in MySQL like set @aintconst = -333 set @arealconst = -9.999 It seems not. Assigning ...
7
votes
2answers
181 views

Why are simple SELECTs on InnoDB 100x slower than on MyISAM?

I have quite an annoying problem. I want to use INNODB as my main database engine and give up on MyISAM as I need the former for using galera-cluster for redundancy. I copied (description follows) ...
0
votes
0answers
42 views

Double subquery is very slow, but independently they are fine

I have this query: SELECT mac, pid, node_category.name, status, computername, user_agent, detect_date, regdate, unregdate, last_dhcp, node.notes, (SELECT ip FROM iplog WHERE iplog.mac = node.mac ...
1
vote
1answer
23 views

mysqldump - select table in database only if it contains a specific string

(I'm new to Database Administrators, and am not a Database Administrator. However I originally asked this question on Stack Overflow (here) but didn't get any answers. Sorry if this is not the right ...
1
vote
3answers
102 views

Why MAX() of SUM() giving wrong output?

I have a table employee id name salary city 1 ram 50000 c1 2 sham 20000 c2 3 jadu 80000 c1 4 madhu 90000 c4 5 hari 10000 c2 6 gopal 34000 c3 7 ...
0
votes
0answers
21 views

Combining 2queries: One filtered Users on Role, One Select users with only one specific role

First query: Selects All users with specific rid ( 3 or 4 or 19 or ...). SELECT u.uid AS uid, u.name AS name, fn.field_full_name_value AS field_full_name_value FROM users u LEFT OUTER ...
0
votes
0answers
9 views

SQL Select a rolling count of total transactions over time [duplicate]

I need to get a set of total transactions over time on a weekly interval. Essentially I need a total-transactions-to-date column. When I group by WEEK(Date) I get the amount of transactions for that ...
2
votes
3answers
39 views

Rolling count of total transactions over time

I need to get a set of total transactions over time on a weekly interval. Essentially I need a total-transactions-to-date column. When I group by WEEK(Date) I get the amount of transactions for that ...
0
votes
1answer
19 views

Count(*) as rolecount, filter by rolecount = 1

How can i filter out the rows who only got rolecount = 1? WHERE rolecount = 1 gives an error. Can't really figure out how to do it. SELECT u.uid AS uid, u.name AS name, u.picture AS picture, ...
0
votes
1answer
27 views

how to optimize grouped select from an already grouped select query

I already had a specific query to get a number of shops, but I couldn't sum the cost field, I kept on getting an error on the sum function, but it worked when I did this; select tab.shop_id, ...
0
votes
0answers
37 views

Nesting multiple INNER JOIN within LEFT OUTER JOIN in sql on deifferent side of keyword

I am having some problems with one of the question's answered in the book "SQL FOR MERE MORTALS". Here is the problem statement Problem Statement Here is the Database Structure The Database ...
2
votes
1answer
54 views

Determining what query was called

I want to reverse engineer what exactly happens to the MySQL database when a product is added in Magento. I will have to reproduce the query, because I would like to manually enter new records using a ...
0
votes
0answers
53 views

Combine two mySQL sum queries into one which use different where clauses

I have two sum quires referencing different tables in mySQL. How can I combine the two in order to calculate the difference between the two values for each user in the database? Query 1: SELECT ...
0
votes
1answer
51 views

Is this statement syntactically correct? [closed]

$q = "SELECT var1, var2, var3 FROM tablename WHERE var_a = '$var_a' AND var_b = '$var_b' AND ( ( var1 = '$var1' AND var2 = '$var2' ) OR ( var1 = '$var2' AND var2 = '$var1' ) )"; This ...
0
votes
1answer
34 views

MySQL add few column exception for TRIGGER UPDATE FOR EACH ROW

How to effectively add column id, name exception for trigger: CREATE TRIGGER updated BEFORE UPDATE ON table1 FOR EACH ROW SET NEW.date=NOW() so that date=NOW() will be affected on updating any ...
0
votes
0answers
15 views

Pasting into PHPMyAdmin

This is probably really simple but I have had a look on the web but can't seem to find an answer. I am experimenting with MySQL + PHPMyAdmin on a WAMPserver stack and was saving queries in Excel When ...
1
vote
1answer
70 views

Reducing execution time for this gnarly SQL

I'm creating an order system of some kind. There is a function that I use to get orders (in PHP) and retrieve the required information about the order. However, it seems that I am pulling a lot of ...
0
votes
0answers
15 views

How does database connection actually works? [duplicate]

I am wondering, on a practical level : what is a database connection? What does it represent for PHP/Java/Ruby/etc to have an opened connection for instance? What about the MySQL deamon? Does it ...
0
votes
1answer
29 views

How to sum the buy order and sell order in one row per each ticker

I have a table containing some trading information of several tickers and I would like to divide the data into sum(Amount) for buy and sell separately, grouping by each ticker. I have one table ...
-1
votes
0answers
45 views

How to select record with biggest value of column [migrated]

Columns: numberIWant, value I would like to get numberIWant number of records, which have biggest value. select max(value) from myTable only returns the max value. I want to find numberIWant that ...
0
votes
3answers
42 views

Select rows where 2 cells not the same

I have the following table: +----+-------+---------+---------------+ | id | owner | variant | EAN | +----+-------+---------+---------------+ | 1 | 101 | black | 1111111111111 | ...
0
votes
1answer
82 views

Splitting Columns

I want to ask a complicated question and I think its advanced a little. I have a table has this design, its an attendance system. I need to split the time if the attendance count per day was not 2: ...
1
vote
0answers
20 views

Can I include extra columns in a m->m mapping table? [duplicate]

I guess this is sort of an odd question, but consider this scenario. table classes (id_pk) table students (id_pk) table students_classes_map (students_id_fk_pk, classes_id_fk_pk, finalExamScore ...
1
vote
1answer
10 views

Not able to update MySQL table using Oracle: Unknown column in 'where clause' {42S22,NativeErr = 1054}

I have the following tables: MySQL table: jti_member_interact CREATE TABLE `jti_member_interact` ( `INT_MEMBER_ID` int(11) NOT NULL, `INT_ID` int(11) NOT NULL AUTO_INCREMENT, `INT_SOURCE` ...
0
votes
1answer
25 views

Does column size increase break SELECT *?

I searched a little bit on this topic before realizing it is somewhat tricky (for me, at least) to come up with an effective search phrase for it because it overlaps with other common topics. So here ...
1
vote
1answer
27 views

Fetch data from same table using two group by clauses in mysql

I have one table name as consultant with 4 fields(id, name,user_type, Created date). I need to write an mysql query for return the count of user_type in each month. In my table, user_type is ...
1
vote
1answer
33 views

MySQL: Find ID with only 2 attached IDs in subtable

I've got 2 tables. 1 containing my Threads and 1 containing the users attached to these threads. I want to find the ThreadID with 2 specific UserIDs attached, no more no less. This is what I've come ...
0
votes
0answers
38 views

Show single value of one column for multiple rows of other columns

I have a SQL query which displays my data results like this. date emp_id emp_name spent_hours 19-08-2013 1024 jack 10 19-08-2013 1024 jack 11 19-08-2013 1024 jack ...
0
votes
1answer
89 views

MySQL 5.1 -> 5.6 problem, select distinct order by limit query stops using index

I'm testing a MySQL 5.1 -> 5.6 upgrade, and I've run into an issue. I have a query that hits a ~30 million row table, selecting distinct IDs with an order by/limit restriction. Sample query is ...
0
votes
1answer
40 views

Need to delete consecutive, unchanged records

I have a rather large MySQL db that is tracking pricing changes for a large number of products. Each entry has a SKU a datetime and a price. Sometimes, there is no change in the price from one time ...
0
votes
1answer
33 views

CASE conditions in SELECT statement

I have the following SELECT statement: SELECT expt_id, iso_stain, test_stain, stain_type CASE WHEN stain_type = 'Blue' THEN iso_stain = 'NA' CASE WHEN statin_type = 'Hematoxylin' THEN ...
1
vote
0answers
27 views

One table for article comments, video comments and photo comments or multiple tables?

First DBA question. Greetings people. I hope I'm not duplicating a question but it's very hard finding database design related questions here (for multiple comment tables), as all 'design' questions ...
3
votes
4answers
195 views

Best practice for a Table with private columns

I have a table with user data, where most of the columns can be public or private (so it will be shown or not on the app) and every user can decide which fields to hide. So far I had a couple of ...
0
votes
1answer
41 views

How do I count the number of different child id's belonging to a parent record?

For instance I have two tables in a music database. Table album and table track. Each track record has (amongst other things), an album_id and an artist_id Each album record has a unique album_id ...
0
votes
1answer
32 views

MySQL Insert with Select

Trying to insert data to a table with values from different tables. INSERT INTO class_teachers_section(class_ref, teachers_ref, section_ref) select (select class.id as class_ref from class ...
2
votes
2answers
57 views

Should I drop a foreign key if I use a soft delete?

"ON UPDATE" scenario never happens in my application. As soft delete is used, "ON DELETE" cascade and restrict scenario never happen as well now. Then, should I just drop foreign key because I have ...
-1
votes
0answers
11 views

Error stored procedure Mysql

I have a table and every month need to delete data for new data are included. I made a stored procedure to automate this process. This table has about 3 million lines in a monthly period. This can ...
0
votes
1answer
64 views

MySQL select with left join query

I have following code. select class.name as classname, class.hours as hours, teachers.first_name as teacherFirstName, teachers.last_name as teacherLastName from teachers,class left join ...
0
votes
1answer
24 views

move content from one table to another table and add a new value

I need to move content from one table to another table, this part is done: INSERT INTO `insc_mwc` (`nome`,`empresa_idempresa`,`cat_mwc_idcat`,`points_pontos`,`n_registo`) SELECT ...
1
vote
1answer
52 views

MYSQL Query - Unexpected result in text messaging database

On a text messaging database I have built, I am trying to return the total amount of messages a user has sent and the total number of messages a user has received. I have the following code: SELECT ...
0
votes
0answers
23 views

MySQL: Select a subset/range of a result

Assuming there's an application for running events (marathons etc.). An event (i.e. a run) has an ID and serveral segments, divided by checkpoints. So here's what we might get: SELECT * FROM segments ...
0
votes
1answer
28 views

MySQL: What is SQL profiler, does it different for MySQL?

Whenever SQL profiling comes in mind, focus goes to two below sections: GUI tools like - MONyog, Neor Profile SQL set profiling =1; Execute Query; show profiles; show profile; I am really confuse ...
1
vote
1answer
43 views

Detect data spikes (loops) in MySQL database and ignore these

i must create some statistics out of a WWW access log database, but i found out that there are some redirect loops after a login if the user has disabled cookies. So there are 10-1000 mostly identical ...
1
vote
1answer
78 views

MySQL: Which join is better between left outer join and inner join

Which join is better peforming if all of them provides the same result? For example, I have a two tables employees(emp_id,name, address, designation, age, sex) and work_log(emp_id,date,hours_wored). ...
0
votes
1answer
45 views

Any way to get database data back?

So I've entered a couple hundred rows of data into a database manually and have begun implementing a Java frontend. However, I got an unexpected result and now when I go back into RazorSQL, the ...