mysql

问题 I was trying to read a very huge MySQL table made of several millions of rows. I have used Pandas library and chunks . See the code below: import pandas as pd import numpy as np import pymysql.cursors connection = pymysql.connect(user='xxx', password='xxx', database='xxx', host='xxx') try: with connection.cursor() as cursor: query = "SELECT * FROM example_table;" chunks=[] for chunk in pd.read_sql(query, connection, chunksize = 1000): chunks.append(chunk) #print(len(chunks)) result = pd

问题 I was trying to read a very huge MySQL table made of several millions of rows. I have used Pandas library and chunks . See the code below: import pandas as pd import numpy as np import pymysql.cursors connection = pymysql.connect(user='xxx', password='xxx', database='xxx', host='xxx') try: with connection.cursor() as cursor: query = "SELECT * FROM example_table;" chunks=[] for chunk in pd.read_sql(query, connection, chunksize = 1000): chunks.append(chunk) #print(len(chunks)) result = pd

问题 I'm trying to create a TLS connection to a Cloud SQL database but I'm getting the following error when trying to prepare a statement: x509: cannot validate certificate for <cloud sql instance ip> because it doesn't contain any IP SANs Here is my setup code: rootCertPool := x509.NewCertPool() pem, err := ioutil.ReadFile("/path/server-ca.pem") if err != nil { log.Fatal(err) } if ok := rootCertPool.AppendCertsFromPEM(pem); !ok { log.Fatal("Failed to append PEM.") } clientCert := make([]tls

问题 I need help with mysql and date_sub(). I have a table call Activity Activity(id,deadline,alert) Activity(1,'2011-04-18','1 DAY'); Activity(2,'2011-04-13','1 MONTH'); Every row in A have an 'alert', this field indicate how time before the deadline an activity have to reported. For example On 2011-04-17 I have to report the activity with 'id' 1 On 2011-03-14 I have to report the activity with 'id' 2 I trying to use date_sub() functions, but I can't use a field as params of this function. Any

问题 i installed xampp version 3.2.1 on my laptop and mysql was working fine on it before but suddenly mysql stopped working while apache and others were working. when i click on start mysql it displays this error i use windows 10 8:52:32 AM [mysql] Status change detected: running 8:52:40 AM [mysql] Status change detected: stopped 8:52:40 AM [mysql] Error: MySQL shutdown unexpectedly. 8:52:40 AM [mysql] This may be due to a blocked port, missing dependencies, 8:52:40 AM [mysql] improper privileges

问题 Hey all, I'm getting an error OperationalError: (1054, "Unknown column 'XX' in 'where clause'") Where XX is the value of CLASS in the following code conn = MySQLdb.connect(host = "localhost",user = "user", passwd = "pass",db = "dbase") cursor = conn.cursor() cursor.execute("""SELECT * FROM %s WHERE course =%s AND sec = %s""" % (str(DEPT),str(CLASS),str(SEC),)) The thing is, I only get this error with certain values, namely, when CLASS contains a letter. I have the table set up as varchar if

问题 I am using the following code: use Doctrine\ORM\Query\ResultSetMapping; ... ... ... ... $em = $this->get( 'doctrine.orm.entity_manager' ); $rsm = new ResultSetMapping(); $query = $em->createNativeQuery( 'CALL procedureName(:param1, :param2)', $rsm ) ->setParameters( array( 'param1' => 'foo', 'param2' => 'bar' ) ); $result = $query->getResult(); //$result = $query->execute(); // Also tried $em->flush(); die(var_dump($result)); I am not getting any thing in the $result parameter. Can anyone

问题 I want to pass Dto as in parameters and call stored procedure in spring jdbc.Is it possible,In doing so? I want to call stored procedures with dto as in paratmeters instead of setting parameters?Because I have large number of parameters. 回答1: At the moment, there is no way to pass (or return) objects in MySQL stored procedures and functions. BUT, MySQL 5.7 have JSON functions, you can pass a varchar parameter and extract values using JSON_EXTRACT function. See MySQL 5.7 manual: Functions That

问题 Looking on advice on clustering of Nodejs and the method of connection to mysql server. Do we open one connection for each child process or just one single connection for all processes? Or do we create a connection pool for all the child processes? Which is the recommended method? one node process var mysql = require('mysql'); var connection = mysql.createConnection({ host : 'example.org', user : 'bob', password : 'secret' }); connection.connect(function(err) { if (err) { console.error('error

问题 This question already has answers here : CSV for Excel, Including Both Leading Zeros and Commas (12 answers) Closed 6 years ago . Exporting select query data from mysql to csv & opening with excel, the leading zeros are gone. Although the column is varchar, when the data gets exported, it writes like 4567 instead of 04567, is there a way to preserve the leading zero while exporting to csv? 回答1: You need to wrap the number in double quotes like: ...,"04567",... , but then it will be