Recent questions tagged SQL

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sql - MySql - Way to update portion of a string?

I'm looking for a way to update just a portion of a string via MySQL query. For example, if I have 10 ... there a way to change 'anothervalue' See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - Difference between Subquery and Correlated Subquery

Is the following piece of SQL Query a normal query or a Correlated Subquery ?? SELECT UserID, FirstName, ... the difference between the both See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - MySQL - Replace Character in Columns

Being a self-taught newbie, I created a large problem for myself. Before inserting data in to my database, I' ... 't achieve that with SQL? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql server - PRINT statement in T-SQL

Why does the PRINT statement in T-SQL seem to only sometimes work? What are the constraints on using it? It seems ... , such as the row count? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - How to implement a Keyword Search in MySQL?

I am new to SQL programming. I have a table job where the fields are id, position, category, location, salary ... ' OR b.catname LIKE '%sales%' See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - Measuring Query Performance : "Execution Plan Query Cost" vs "Time Taken"

I'm trying to determine the relative performance of two different queries and have two ways of measuring this available ... takes less time :) See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - OVER clause in Oracle

What is the meaning of the OVER clause in Oracle? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql server - Move SQL data from one table to another

I was wondering if it is possible to move all rows of data from one table to another, that match a ... using SQL Server 2008 Management Studio. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql server ce - Using Entity Framework with an SQL Compact Private Installation

I am using Entity Framework 4 in a desktop application with SQL Compact. I want to use a private installation ... ? Thanks for your help. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - How to show row numbers in PostgreSQL query?

I'd like to show the observation number for each record returned by a PostgreSQL query. I think in 8. ... functions can perform this capability. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - MySQL CONCAT returns NULL if any field contain NULL

I have following data in my table "devices" affiliate_name affiliate_location model ip os_type os_version cs1 inter Dell 10. ... -10.125.103.28- See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - What are views good for?

I'm just trying to get a general idea of what views are used for in RDBMSes. That is to say, I know what ... . This is partly a concept check.) See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - How to do IF NOT EXISTS in SQLite

I am trying to port this line from MS SQL Server to SQLite IF NOT EXISTS(SELECT 1 FROM EVENTTYPE WHERE ... simple? Is there a workaround? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - How do I ALTER a PostgreSQL table and make a column unique?

I have a table in PostgreSQL where the schema looks like this: CREATE TABLE "foo_table" ( "id" serial NOT NULL ... table by ALTER-ing the table. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql server data tools - Visual Studio 2015 Database Project directory contains a file with extension jfm

Assuming we have a database project called MyDatabase then a file called MyDatabase.jfm appears in the root of the ... where it came from... See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - Do all columns in a SELECT list have to appear in a GROUP BY clause

My lecturer stated: All column names in SELECT list must appear in GROUP BY clause unless name is used only in an ... why it should be true... See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - Select a random sample of results from a query result

This question asks about getting a random(ish) sample of records on SQL Server and the answer was to use ... that will return millions normally? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - MySQL INNER JOIN select only one row from second table

I have a users table and a payments table, for each user, those of which have payments, may have multiple associated ... .id WHERE u.package = 1 See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - PostgreSQL delete with inner join

DELETE B.* FROM m_productprice B INNER JOIN m_product C ON B.m_product_id = C.m_product_id WHERE C.upc = '7094' ... the problem with my query? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - MySQL LEFT JOIN 3 tables

I have 3 tables: Persons (PersonID, Name, SS) Fears (FearID, Fear) Person_Fear (ID, PersonID, FearID) Now I'd ... What am I doing wrong here? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - What is it exactly a BLOB in a DBMS context

What is it a BLOB? How can I use it? What are the differences between DBMS's BLOBs. I would like to save ... then read that BLOB with a library. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql server - Last executed queries for a specific database

I know how to get the last executed queries using the following SQL in SSMS - SELECT deqs.last_execution_time AS [ ... to do this from SSMS. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - creating a random number using MYSQL

I would like to know is there a way to select randomly generated number between 100 and 500 along with a select ... help me out. Thank you See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - Naming of ID columns in database tables

I was wondering peoples opinions on the naming of ID columns in database tables. If I have a table called ... peoples thoughts on the topic? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - How to enable Ad Hoc Distributed Queries

When I run a query with OPENROWSET in SQL Server 2000 it works. But the same query in SQL Server ... Distributed Queries' by using sp_configure See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - What are the benefits of using database cursor?

It is based on the interview question that I faced. Very short definition can be It can be used to manipulate ... that we should use cursor? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - How to get current date & time in MySQL?

Is there a value or command like DATETIME that I can use in a manual query to insert the current date and ... add the current date and time. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - Why is iterating through a large Django QuerySet consuming massive amounts of memory?

The table in question contains roughly ten million rows. for event in Event.objects.all(): print event This causes ... I'm using PostgreSQL.) See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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