大约有 1,948 项符合查询结果（耗时：0.0178秒） [XML]
SQL query to group by day
... (from Q8-Coder):
GROUP BY dateadd(DAY,0, datediff(day,0, created))
For MySQL:
GROUP BY year(datefield), month(datefield), day(datefield)
or better (from Jon Bright):
GROUP BY date(datefield)
For Oracle:
GROUP BY to_char(datefield, 'yyyy-mm-dd')
or faster (from IronGoofy):
GROUP BY trun...
Update a column value, replacing part of a string
I have a table with the following columns in a MySQL database
6 Answers
6
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Explicitly set Id with Doctrine when using “AUTO” strategy
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Although your solution work fine with MySQL, I failed to make it work with PostgreSQL as It's sequence based.
I've to add this line to make it work perfectly :
$metadata->setIdGenerator(new \Doctrine\ORM\Id\AssignedGenerator());
Best regards,
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Reason for Column is invalid in the select list because it is not contained in either an aggregate f
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@davidblaine, MySQL has a function GROUP_CONCAT() for that. dev.mysql.com/doc/refman/5.5/en/… But in standard SQL, each column should contain only one value. That's fundamental to relational theory too.
– Bill Kar...
How to do 3 table JOIN in UPDATE query?
...need a visual aid to get your joins correct: browse-tutorials.com/tutorial/mysql-joins-visual-representation
– ram4nd
Jan 27 '17 at 9:29
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What is the simplest SQL Query to find the second largest value?
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I see both some SQL Server specific and some MySQL specific solutions here, so you might want to clarify which database you need. Though if I had to guess I'd say SQL Server since this is trivial in MySQL.
I also see some solutions that won't work because they fail to...
Format number to 2 decimal places
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You want to use the TRUNCATE command.
https://dev.mysql.com/doc/refman/8.0/en/mathematical-functions.html#function_truncate
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How to select the nth row in a SQL database table?
... http://troels.arvin.dk/db/rdbms/#select-limit.
Basically, PostgreSQL and MySQL supports the non-standard:
SELECT...
LIMIT y OFFSET x
Oracle, DB2 and MSSQL supports the standard windowing functions:
SELECT * FROM (
SELECT
ROW_NUMBER() OVER (ORDER BY key ASC) AS rownumber,
columns
F...
INSERT INTO … SELECT FROM … ON DUPLICATE KEY UPDATE
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MySQL will assume the part before the equals references the columns named in the INSERT INTO clause, and the second part references the SELECT columns.
INSERT INTO lee(exp_id, created_by, location, animal, starttime, endtime...
Retrieve column names from java.sql.ResultSet
...equired libraries
import java.util.*;
import java.sql.*;
public class MySQLExample {
public void run(String sql) {
// JDBC driver name and database URL
String JDBC_DRIVER = "com.mysql.jdbc.Driver";
String DB_URL = "jdbc:mysql://localhost/demo";
// Database credentials
Str...