Questions tagged [sql]
Structured Query Language (SQL) is a language for querying databases. Questions should include code examples, table structure, sample data, and a tag for the DBMS implementation (e.g. MySQL, PostgreSQL, Oracle, MS SQL Server, IBM DB2, etc.) being used. If your question relates solely to a specific DBMS (uses specific extensions/features), use that DBMS's tag instead. Answers to questions tagged with SQL should use ISO/IEC standard SQL.
672,778
questions
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SQL not allowing deletion of related data
In SQL I have:
CREATE TABLE Customer(
cust_id INT NOT NULL PRIMARY KEY CHECK (cust_id > 0),
full_name TEXT NOT NULL,
phone TEXT NOT NULL,
...
- 11
0
votes
0
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7
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first 2 makes query slower than when I use first 1 in sql query in informix database
I have a query on a huge table (126738484 records) on an informix database server;
this query returns only one record.
when I use "first 1 " in the select statement, it runs quickly but ...
-1
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0
answers
18
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ER_BAD_FIELD_ERROR in SQL
CREATE DATABASE IF NOT EXISTS RAIL;
USE RAIL;
CREATE TABLE IF NOT EXISTS train (
t_id INT NOT NULL AUTO_INCREMENT,
t_rating INT NOT NULL,
t_name VARCHAR(20) NOT NULL,
t_price INT NOT ...
- 11
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1
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13
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laravel Eloquent ::has() QueryException on different connection
I have two databases,
db1 :
users table
db2 :
infos table
Each table I created has a Models, and I set a different connection for each one:
User.php => protected $connection = "db1";
...
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0
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22
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Check if a table has any records [duplicate]
Considering a situation to check whether a table has any records or not, Is there any difference in the performance or execution speed among the two following queries? If yes, what is the logical ...
0
votes
2
answers
38
views
Using arrays in `WHERE IN` statements
There are the following table structures and data:
CREATE TABLE t_source_category (
id INT PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
label varchar(255) NOT NULL,
path varchar(255) NOT NULL,
...
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-1
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1
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26
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Why does this SQL command give the error "Unknown statement type"? [closed]
I'm new to SQL and do not really understand why this:
INSERT INTO users (highscore); VALUES ('1');
gives me an error. Why does this not work?
I'm trying to save my high score in the database so I can ...
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-4
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34
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Spotting missing (null) rows in a table
I have three tables:
Guests
Meals
Dates
Most guests place three orders a day within a week period which is set up as a CTE with the following code:
with Dates(Date) as
(
select cast(@date1w as ...
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-4
votes
1
answer
40
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How do I split a string with inconsistent data?
I have some imperial distances (miles/furlongs/yards) in a column which I am looking to convert into just furlongs. However, the data is inconsistent. Sometimes there is a furlongs value, sometimes ...
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0
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29
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How do I generate rows of predefined values from a SELECT statement? [duplicate]
In SQLite I want to return a list that I type in myself (for further left join SQL commands):
ABC
DEF
GHI
Not existing in any table but manually entered strings (like how SELECT 'ABC' returns ABC, ...
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1
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1
answer
28
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SQL query to update duplicate data
I had a bug in my code which created a lot of new users with the same email (id was the PK), and this caused my Usage table to save data of the new ID that was created.
User table:
user_id | ...
- 1,182
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votes
1
answer
23
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How To use QSqlQuery::bindValue
I have this snippet :
int id = m_AddItemCandidate->getId();
QString s = "INSERT INTO studied_substantives (subst_id, no_singular, no_plural, meaning) ";
s = s + "VALUES(:id,...
1
vote
1
answer
26
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How to use one PS dataset in a WHERE-OBJECT of another dataset
I have been using PS for about 10 years. Today I am stuck with finding a solution to a problem where I want to have items used in a WHERE-Object loaded from a SQL table. From what I have read, I need ...
- 11
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34
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How can I fix this RLS policy issue with Supabase on .insert()?
I am in the process of creating a habit tracking app and am using Supabase PostgreSQL. I am implementing RLS in the habit table but cannot for all that is good figure out this issue. On the click of ...
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-1
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2
answers
46
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Convert multiple MYSQL rows to only one array column
I have a simple database with the user and the country tables.
Which user belongs to only one country.
Which country has a list of users.
Right now Im using group_concat (code below) and its working ...
- 135