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When to use Hadoop, HBase, Hive and Pig?
...ru some SQL like language
To replace daily aggregation data generated thru MySQL with Hive
Build Custom reports thru queries in Hive
Architecture Options
I benchmarked the following options:
Hive+HDFS
Hive+HBase - queries were too slow so I dumped this option
Design
Daily log Files were tr...
Is the primary key automatically indexed in MySQL?
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According to http://dev.mysql.com/doc/refman/5.0/en/constraint-primary-key.html it would appear that this is would be implicit
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Convert from MySQL datetime to another format with PHP
I have a datetime column in MySQL.
18 Answers
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MySQL: Large VARCHAR vs. TEXT?
I've got a messages table in MySQL which records messages between users. Apart from the typical ids and message types (all integer types) I need to save the actual message text as either VARCHAR or TEXT. I'm setting a front-end limit of 3000 characters which means the messages would never be inserte...
MySQL select one column DISTINCT, with corresponding other columns
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@Full Decent you can't, according to MySQL documentation: "The server is free to choose any value from each group, so unless they are the same, the values chosen are indeterminate.". In practice I've successfully used this kind of queries with ORDER BY clause, ...
python-pandas and databases like mysql
...ing a DBI compatible library. We can look at two short examples using the MySQLdb and cx_Oracle libraries to connect to Oracle and MySQL and query their data dictionaries. Here is the example for cx_Oracle:
import pandas as pd
import cx_Oracle
ora_conn = cx_Oracle.connect('your_connection_string'...
ERROR: Error 1005: Can't create table (errno: 121)
I have troubles with forward engineering my MySQL database into WAMP server..
I was going to post an image of the schema but as this is my first post I can't.
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MySQL Conditional Insert
...his, dual is a table with one row only (found originally in Oracle, now in mysql too). The logic is that the SELECT statement generates a single row of data with the required values, but only when the values are not already found.
Alternatively, look at the MERGE statement.
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MySQL and GROUP_CONCAT() maximum length
I'm using GROUP_CONCAT() in a MySQL query to convert multiple rows into a single string.
However, the maximum length of the result of this function is 1024 characters.
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How to do a regular expression replace in MySQL?
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With MySQL 8.0+ you could use natively REGEXP_REPLACE function.
12.5.2 Regular Expressions:
REGEXP_REPLACE(expr, pat, repl[, pos[, occurrence[, match_type]]])
Replaces occurrences in the string expr that match the regular express...