Recent questions tagged sql

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In my MySQL database, there is a table which has 2,000,000 records. Now, I would like to insert another ... efficent data insertion in my case? 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 semi-join in database?

I am having trouble while trying to understand the concept of semi-join and how it is different from conventional ... help me to understand it? 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 syntax not evaluating not equal to in presence of NULL

I am having trouble with a mysql query. I want to exclude values of 2. So I thought I would do following: ... suggest a fix. Thanks in advance! 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 - Compare dates in T-SQL, ignoring the time part

I'm using MS SQL 2005, and I want to check two dates for equality, but ignoring the time part. I know I ... checking for equality, that is all. 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 - How can I insert binary file data into a binary SQL field using a simple insert statement?

I have a SQL Server 2000 with a table containing an image column. How do I insert the binary data of a file ... ( FileId int, FileData image ) 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 - The ORDER BY clause is invalid in views, inline functions, derived tables, subqueries, and common table expressions

The ORDER BY clause is invalid in views, inline functions, derived tables, subqueries, and common table expressions, ... RowNum BETWEEN 1 and 5 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 - Is it possible to use `SqlDbType.Structured` to pass Table-Valued Parameters in NHibernate?

I want to pass a collection of ids to a stored procedure that will be mapped using NHibernate. This technique was ... on the SQL Server side. 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 - Show all duplicated rows

suppose I have following sql table objid firstname lastname active 1 test test 0 2 test test 1 3 test1 test1 ... lastname test test test2 test2 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 are aggregate functions not allowed in where clause

I am looking for clarification on this. I am writing two queries below: We have a table of employee ... you please validate my understanding. 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 count performance on very big tables

I have a table with more than 100 millions rows in Innodb. I have to know if there is more than 5000 rows ... day. It's still working fine. 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 NULL values affect performance in a database search?

In our product we have a generic search engine, and trying to optimze the search performance. A lot of the tables ... Oracle and MS SQL Server. 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 JOIN with array type with array elements order, how to implement?

I have two tables in database: CREATE TABLE items( id SERIAL PRIMARY KEY, ... some other fields ... table for specific row? 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 - ActiveRecord find_each combined with limit and order

I'm trying to run a query of about 50,000 records using ActiveRecord's find_each method, but it seems to ... and respecting my sort criteria? 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 - Random record from a database table (T-SQL)

Is there a succinct way to retrieve a random record from a sql server table? I would like to randomize my unit ... then re-run if null. Ideas? 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 - SQL INSERT INTO from multiple tables

this is my table 1: NAME AGE SEX CITY ID Clara 22 f New York 1 Bob 33 m Washington 2 Sam 25 m Boston 3 ... I merge all 3 tables into one 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 - Do I need to create indexes on foreign keys on Oracle?

I have a table A and a table B. A has a foreign key to B on B's primary key, B_ID. For some ... the existence of a foreign key provide that? 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 the meaning of SELECT ... FOR XML PATH(' '),1,1)?

I am learning sql in one of the question and here I saw usage of this,can some body make me understand what ... (select distinct ID from @t )t 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 - Historical / auditable database

This question is related to the schema that can be found in one of my other questions here. Basically in ... that might make. Thanks. 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 - What are the differences between Merge Join and Lookup transformations in SSIS?

Hi I'm new to SSIS packages and writing a package and reading up about them at the same time. I need to ... would be very helpful. 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 - ORA-01652: unable to extend temp segment by 128 in tablespace SYSTEM: How to extend?

I have a large Oracle table, which contains 542512 rows. It has three columns and when I try to create an ... . Any help would be appreciated. See Question&Answers more detail:os...

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

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197 views

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sql - Database in use error with Entity Framework 4 Code First

I have an MVC3 and EF 4 Code First application, which is configured to change the DB when the model changes, ... have to implement it myself. See Question&Answers more detail:os...

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

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269 views

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sql server - MySQL - Meaning of "PRIMARY KEY", "UNIQUE KEY" and "KEY" when used together while creating a table

Can anyone explain about the purpose of PRIMARY KEY, UNIQUE KEY and KEY, if it is put together in a single ... I convert this query to MSSQL? 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 - Should I commit or rollback a read transaction?

I have a read query that I execute within a transaction so that I can specify the isolation level. Once ... connections? Any other differences? 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 - Update multiple columns in SQL

Is there a way to update multiple columns in SQL server the same way an insert statement is used? Something like: ... if you have 100+ columns. 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 - Is this a good way to model address information in a relational database?

I'm wondering if this is a good design. I have a number of tables that require address information (e.g. street, ... like I'm creating a leak). See Question&Answers more detail:os...

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

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305 views

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sql server - What are row, page and table locks? And when they are acquired?

I want to know more about different types of locks Database Engine aquires. What are Row Locks Page Locks ... me understand these concepts. See Question&Answers more detail:os...

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

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224 views

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sql - How to check the existence of a row in SQLite with Python?

I have the cursor with the query statement as follows: cursor.execute("select rowid from components where name = ?", ( ... . How do I do that? 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 check if field is null or empty in MySQL?

I am trying to figure out how to check if a field is NULL or empty. I have this: SELECT IFNULL(field1, ... Any idea how to accomplish this? See Question&Answers more detail:os...

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

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