Questions tagged as 'mysql'

Tagged questions
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MySQL does not return data in a column

I have a database where sometimes there is no data in some columns, I would like to know how I could know that this column is null . I've tried with if(!_Rellenar.HasRows) { isNull = false; } And with: if(!_Rellenar.Read()) {...
asked by 14.10.2018 / 23:05
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MySQL query repeated data

I'm doing a query on phpMyadmin, everything worked fine, but I was taking data from other tables, however, when I added the LEFT JOIN, everything was still working perfectly. The problem is when in the SELECT I put the name of the column to be d...
asked by 08.10.2018 / 22:14
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Select and then Insert

I need to do a procedure stored in MySQL: I have a select where I rescue data: select columna1, columna1, columna1, columna1, columna1 from TB1 and these data taken I need to pass them to a new table ( TB2 ): Talves is as simple...
asked by 12.09.2018 / 18:25
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Problem with mysql and php

I have the following doubt, I am doing a search engine, that I look for in my database a product that contains some letter in its name, I make the query in phpmyadmin and all good, it works for me, the problem comes when I pass by parameter from...
asked by 09.09.2018 / 07:47
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As an addition to a 2 foreign key that are both primary?

My problem is as follows, I have 2 COORDINATION and NACCLE_ACADEMIC tables, the relationship between them is N: M (many to many), the structure of the table COORDINATION and NACCLEO_ACADÉMICO the table is as follows: CREATE TABLE coord...
asked by 19.09.2018 / 04:09
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Notice: Trying to get property of non-object

I'm having the following error: Notice: Trying to get property 'idDia' of non-object in C:\wamp64\www\backend-trabajo-final\profesionales\select-profesionales-para-posible-servicio.php on line 26 (So, with each of the properties I try...
asked by 24.09.2018 / 15:38
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Calculate result with previous record and update in the new record

I want to take a tour of the 'data' table and in each of the registers I need to take the Mileage from the previous record, then subtract New Mileage - Old Mileage and divide it between Liters to get Efficiency and assign it to the record, but I...
asked by 22.09.2018 / 02:42
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Why does the same date appear on all Users?

I am in Java, and I want to show the users that I have in the database, I make the query and it collects it well, I insert them well in an ArrayList and when I show it, only the date of birth of the last user appears. Why? try { senten...
asked by 12.11.2018 / 14:35
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Insert and Search in Datetime field

I'm trying to insert a date with milliseconds, but I can not do it. The bash date has the following format: "%d%m%Y%H%M%S%2N" While in BBDD I see the following: MariaDB [db]> INSERT INTO access_wifi(DATA) VALUES ('0511201813450367'); Q...
asked by 05.11.2018 / 15:47
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last question id inserted (mysql)

Hello, good morning, everyone. I need to make an insert to an X table and immediately make an insert in an Xx table. The insert to the first table works without problems, but the particularity that the second insert has as key the ID th...
asked by 24.08.2018 / 15:52