In this article I will try to explain the “Fastest way to select a random row from a big MySQL table”. Sometimes application developer requires select a random id , rollnumber or something like that from a big MySQL table. If the MySQL table has more than 100K rows traditional SQL will...
SELECT column FROM tableORDER BYRANDOM()LIMIT 1 1. Select a random row with Microsoft SQL Server: SELECT TOP 1 column FROM tableORDER BYNEWID() 1. Select a random row with IBM DB2 SELECT column, RAND() as IDX FROM table ORDER BY IDX FETCH FIRST 1 ROWS ONLY 1. ThanksTim Select a r...
The following SQL defines a table holding images. Imagine that we wish to pick up 10 random rows from it. In our test, we fill it with ~50k (524,288) rows, approximately 90 MB storage space. Note that we also have a PRIMARY KEY index on “id”, and it uses ~5 MB storage space...
You may need asql querythat willselect top n recordsorrandom n recordsfor each categoryin a table. Thet-sql querythat will solve this problem may be difficult for first timers, especially if you are working onMS SQL Server 2000. Now, with thet-sql enhancementsinMicrosoft SQL Server 2005th...
SQL - SELECT TOP n or SELECT TOP Random n Rows From a Table For Each Category or Group You may need asql querythat willselect top n recordsorrandom n recordsfor each categoryin a table. Thet-sql querythat will solve this problem may be difficult for first timers, especially if you ar...
on the database. MySQL Cluster uses the READ COMMITTED mode, so not REPEATABLE READ. To display in ascending order you use ORDER BY ASC if I remember correctly the SQL for it. Subject Views Written By Posted ndbcluster: select * from table is showing random rows ...
sql = "INSERT /*+ append enable_parallel_dml parallel(4) */ INTO test2 SELECT * FROM test"; s = connection.prepareStatement(sql); lnRows = s.executeUpdate(); 注意,需要设置AUTOCOMMIT为ON/true。 若设置AUTOCOMMIT为OFF/false。 autocommit: OFF ...
1、SQL Server数据库 select top 10 * from table_name; 2、DB2数据库 select * from table_name fetch first 10 rows only; 3、Oracle数据库 select * from table_name where rownum <=10; 4、MySQL数据库 select * from table_name limit 10; ...
INSERT INTO SELECT语句通过 Hint 使用append加上enable_parallel_dml来走旁路导入。 使用限制 只支持 PDML(Parallel Data Manipulation Language,并行数据操纵语言),非 PDML 不能用旁路导入。 在导入过程中无法同时执行两个写操作语句(即不能同时写一个表),因为导入过程中会先加表锁,并且整个导入过程中只能进行读操作...
SQLSelect(数据库, 数据表[, 字段名[, 条件]]) 参数 参数数据类型解释 数据库 字符串 数据库的文件路径 数据表 字符串 要操作的表名 字段名 字符串 可选参数,要查询的字段名,省略默认为获取所有字段 条件 字符串 可选参数,要查询的过滤条件,语法参照sqlite语法 返回值 表 ,返回查到的结果。 示例 复制 ...