T Sql Tutorial

SQL Date-time subtraction statement This tutorial takes advantage of the DateDiff function to subtract the dates of the database tutorials Oh, and here's how to subtract n from the MSSQL date. Two date subtraction 1 in SQL, Days of difference select trunc (sysdate, ' yyyy ')-to_date (' 2009-01-04 ', ' yyyy ') from dual; 2, the difference of the number of months select Months_b ...

MySQL optimization is very important. The most common and most needed optimization is limit. 　　The limit of MySQL brings great convenience to paging, but when the amount of data is large, the performance of limit is reduced dramatically. The same is 10 data select * FROM Yanxue8_visit limit 10000,10 and select * from Yanxue8_visit limit 0,10 is not a quantitative level ...

Two php tutorials export excel instance <? Php header ("content-type: application / vnd.ms-excel; charset = gbk"); header ("content- disposition: attachment; filename = test_data.xls" ...

The concatenation (join) and segmentation (split) of MSSQL strings are often used by masters using select number from Master. spt_values WHERE type = ' P ', this is a good way to do it, but there are only 2048 digits, and the statement is too long and not convenient. In short, a digital assistance table (100,000 or 1 million per person needs), you deserve it. 2. Useful index of the calendar table: ★★★☆☆ "SQL Programming Style" a book suggests an enterprise ...

PHP tutorials Statistics static HTML page Browse access number code//count.php $aid = isset ($_get[' aid ')? $_get[' aid ']: '; $t = isset ($_get[' t '])? $_get[' t ']: '; if (Intval ($aid)) {if ($t = = ' show ') {echo &q ...

PHP Tutorial Export data to CSV file include (".  /admin/inc/inc.php ");  $times = time (); $filename = $times. "  CSV ";  $a = "contact person, telephone number, community, required materials, notes, application time n"; $days = ...

In the PHP tutorial +mysql Tutorial Database Tutorial in the paging code than the previous ASP tutorials, the ASP.net tutorial is relatively easy, because MySQL support limit,0,n so that you can easily and quickly get the records to read, so let's look at the instance function  GetPage ($talbe, $choose, $url) {global $page, $db, $sortname; $query = $db->quer ...

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