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Opposite of %in%: exclude rows with values specified in a vector
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If you look at the code of %in%
function (x, table) match(x, table, nomatch = 0L) > 0L
then you should be able to write your version of opposite. I use
`%not in%` <- function (x, table) is.na(match(x, table, nomatch=NA_integer_))
Another way is:
function (x,...
Strings as Primary Keys in SQL Database [closed]
... key then you should probably use it. This all depends on the size of the table you're making it for and the length of the string that is going to be the primary key (longer strings == harder to compare). I wouldn't necessarily use a string for a table that has millions of rows, but the amount of p...
typecast string to integer - Postgres
I am importing data from a table which has raw feeds in Varchar, I need to import a column in varchar into a string column. I tried using the <column_name>::integer as well as to_number(<column_name>,'9999999') but I am getting errors, as there are a few empty fields, I need to retri...
How to Join to first row
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Excellent, that works; moving TOP 1 from derived table clause to join clause.
– Ian Boyd
Jan 11 '10 at 16:54
111
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Insert current date in datetime format mySQL
...re the current time just use MYSQL's functions.
mysql_query("INSERT INTO `table` (`dateposted`) VALUES (now())");
If you need to use PHP to do it, the format it Y-m-d H:i:s so try
$date = date('Y-m-d H:i:s');
mysql_query("INSERT INTO `table` (`dateposted`) VALUES ('$date')");
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搭建高可用mongodb集群（四）—— 分片 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...需要分片的集合和片键
db.runCommand( { shardcollection : "testdb.table1",key : {id: 1} } )
我们设置testdb的 table1 表需要分片，根据 id 自动分片到 shard1 ，shard2，shard3 上面去。要这样设置是因为不是所有mongodb 的数据库和表 都需要分片！
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Fastest Way to Find Distance Between Two Lat/Long Points
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Create your points using Point values of Geometry data types in MyISAM table. As of Mysql 5.7.5, InnoDB tables now also support SPATIAL indices.
Create a SPATIAL index on these points
Use MBRContains() to find the values:
SELECT *
FROM table
WHERE MBRContains(LineFromText(CONCAT(
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How to customize the background color of a UITableViewCell?
...ike to customize the background (and maybe the border too) of all of the UITableViewCells within my UITableView. So far I have not been able to customize this stuff, so I have a bunch of white background cells which is the default.
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Div width 100% minus fixed amount of pixels
How can I achieve the following structure without using tables or JavaScript? The white borders represent edges of divs and aren't relevant to the question.
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初窥InnoDB的Memcached插件 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...件所需要的配置信息：
mysql> USE innodb_memcache
mysql> SHOW TABLES;
+---------------------------+
| Tables_in_innodb_memcache |
+---------------------------+
| cache_policies |
| config_options |
| containers |
+---------------------------+
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