Recent questions tagged MySQL

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The problem I first had with the following query was that the group by clause was performed before the order by: ... cases I put it up against? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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mysql - ERROR 1136: Column count doesn't match value count at row 1

I get the Error: Column count doesn't match value count at row 1. But I've checked and rechecked my query and ... a string, not an enum type. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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mysql - Handling foreign key exceptions in PHP

What is the best way in PHP to handle foreign key exceptions on a mysql database? Is there a mysql class ... and delete the offending records. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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mysql - optimize select query with ORDER BY and MATCH AGAINST

The following query takes 25 seconds with 2 table joins. The first posts table has 150,00 rows, topics ... .php?115,418955,418955#msg-418955 See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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mysql - Codeigniter/PHP check if can connect to database

I'd like to backup my read replica(i.e., slave) database with my master database but this simple boolean I ... how to do this in Codeigniter? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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926 views

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mysql - How to select ORDER BY column and RAND() both?

Hello dear friends. mysql_query("SELECT id FROM tb_table ORDER BY num ASC, ORDER BY RAND() LIMIT 1"); is ... and choose one of them randomly. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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mysql - SQL query dynamic table name in FOR

I have a table tbl1 which has a column tbl_names. This column contains the name of some other tables. Now I ... and execute first query? Thanks See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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920 views

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mysql - How do I reset sequence numbers to become consecutive?

I've got a mysql table where each row has its own sequence number in a "sequence" column. However, when ... are displayed within the app. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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mysql - Using Trigger to update table in another database

im using the following trigger to update the user table in another database in mysql 5.0.7 The creation of trigger ... .id; END; | delimiter ; See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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780 views

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mysql - What is the cost of indexing multiple db columns?

I'm writing an app with a MySQL table that indexes 3 columns. I'm concerned that after the table reaches a ... 25 and 200 records a day. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.1k views

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mysql - What makes the big difference between a backtick and an apostrophe?

What is the reason that the following two queries give wildly different results? MariaDB [mydatabase]> SELECT ... meaning of the apostrophe. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.3k views

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mysql - Why is InnoDB table size much larger than expected?

I'm trying to figure out storage requirements for different storage engines. I have this table: CREATE TABLE `mytest` ... a 4-byte unsigned int? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.1k views

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mysql - No suitable driver found for jdbc in Spark

I am using df.write.mode("append").jdbc("jdbc:mysql://ip:port/database", "table_name", properties) to insert ... driver found for jdbc" error. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.2k views

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mysql - At-Sign in SQL statement before column name

I have an INSERT statement in a PHP-file wherein at-signs (@) are occurring in front of the column name. ... refman/5.0/en/load-data.html See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.1k views

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mysql - Installing phpMyAdmin onto Amazon EC2 instance

I've configured my EC2 instance as a LAMP, following Amazon's tutorial. That appears to be functioning correctly ( ... I cannot figure out what. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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915 views

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mysql - Find the average of two combined columns in sql

I want to find the avg of the total of two columns. I want to count the total of col1 and the total of col2 ... (*)) FROM test WHERE uid=5 ) See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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mysql - ld: library not found for -lzstd while bundle install for mysql2 gem Ruby on macOS Big Sur 11.4

while running bundle install An error occurred while installing mysql2 (0.5.3), and Bundler cannot continue. Make ... run: brew reinstall mysql See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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3.8k views

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mysql - C# Entity Framework: Keyword not supported: 'port'

Hello I have more than one project connecting to a certain DB that is CodeFirst Entity Framework. All ... system.webServer> </configuration> See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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3.7k views

2 answers

mysql - mysqldump command not working?

I am using mysqldump to take backup of my database, but the command is not working.. the command i am using ... any thing wrong in the command? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.3k views

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mysql - java.sql.SQLException: Unknown system variable 'tx_isolation'

I am using play framework and I want to connect db, but I can't because I am getting following error: play ... first time... Thank you. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.2k views

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mysql - Duplicate entry '2147483647' for key 1

Strange problem I can't seem to get my head around. I have a table in a MySQL database with the following ... have any ideas? Many thanks! See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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950 views

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mysql - Must database primary keys be integers?

I always see MySQL database primary keys as integers. Is that because primary keys must be integers, or because of ... a varchar in the future. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.1k views

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mysql - Which one is faster: correlated subqueries or join?

I know we can do correlated subqueries and join. But which one is faster? Is there a golden rule or I must measure both? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.0k views

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mysql - PHP convert datetime to seconds

I have a datetime value in mysql '2010-12-08 16:12:12' that I'd like to get the seconds to that date using PHP, ... -12-08 16:12:12',now())) See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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986 views

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mysql - Alter a live table to make a key non-unique

I saw some other questions related to this, but they were not MySQL. The database is a live database, so I ... it shouldn't cause any problems. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.1k views

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mysql - Sort by JSON field values

I have a table with json values like this: -Table 1 id | name | data ------+----------+----- ... ! P.S: city_name have UTF-8 characters. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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927 views

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mysql - UNIQUE Constraint, only when a field contains a specific value

I'm trying to create a UNIQUE INDEX constraint for two columns, but only when another column contains the value 1. ... I made myself clear. : See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.3k views

1 answer

mysql - How to join three tables to get Sum

I have three tables: Products, Purchase, Invoice Product table: Producct_no Name 1 A 2 B 3 C Purchase table ... get the results properly. thanks See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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