AI代码解释 ---Table structureforstudent---DROPTABLEIFEXISTS`student`;CREATETABLE`student`(`id`int(11)NOTNULLAUTO_INCREMENTCOMMENT'id',`sno`varchar(20)CHARACTERSETutf8COLLATEutf8_unicode_ciNULLDEFAULTNULLCOMMENT'学号',`sname`varchar(10)CHARACTERSETutf8COLLATEutf8_unicode_ciNULLDEFAULTNULLCOMMENT'学生...
-- Skipping the column list, but keeping the values in orderINSERTdbo.ProductsVALUES(75,'Tire Bar',NULL,'Tool for changing tires.')GO 只要在默认架构中访问和更改表,架构名称就是可选的。 由于ProductDescription列允许 Null 值,而且没有提供值,因此可以从语句中完全删除ProductDescription列的名称和值。
CREATE TABLE t1 (a INT, b INT, c AS a/b); CREATE UNIQUE CLUSTERED INDEX Idx1 ON t1(c); INSERT INTO t1 VALUES (1, 0); 有关详细信息,请参阅 计算列上的索引。 索引中的包含列 可以将非键列(称为包含列)添加到非聚集索引的叶级别,从而通过涵盖查询来提高查询性能。 也就是说,查询中引用...
String sql="SELECT u.id, name, age, sum(price) "+"FROM users AS u join orders AS o ON u.id = o.user_id "+"WHERE age >= 20 AND age <= 30 "+"GROUP BY u.id, name, age "+"ORDER BY u.id";// 创建SqlParser, 用于解析SQL字符串SqlParser parser=SqlParser.create(sql,SqlParse...
For more information, see Create user-defined functions (Database Engine). Computed column interoperability Functions have the following properties. The values of these properties determine whether functions can be used in computed columns that can be persisted or indexed. 展开表 PropertyDescriptionNotes...
'mutate_type', 'appendonly'); --day是分区列,要出现在视图的group by的条件中 CREATE MATERIALIZED VIEW mv_sales_p AS SELECT day, hour, avg(amount) AS amount_avg FROM base_sales_p GROUP BY day, hour; COMMIT; create table base_sales_20220101 partition of base_sales_p for values in('202...
(4)) +'Sales'+/* Build a VALUES clause. */' VALUES (@InsOrderID, @InsCustID, @InsOrdDate,'+' @InsOrdMonth, @InsDelDate)';/* Set the value to use for the order month because functions are not allowed in the sp_executesql parameter list. */SET@OrderMonth =DATEPART(mm, @Prm...
@Testpublic void forEachInsert() {System.out.println("forEachInsert 插入开始===");long start = System.currentTimeMillis();for (int i = 0; i < list.size(); i++) {userMapper.insert(list.get(i));}System.out.println("foreach 插入耗时:"+(System.currentTimeMillis()-start));} 三、...
postgres=# CREATE TABLE t_native_range_default PARTITION OF t_native_range DEFAULT; CREATE TABLE postgres=# insert into t_native_range values(1,'2016-09-01',1); INSERT01 list 分区表 表格通过明确的键值进行分区。 创建主分区 postgres=# create table t_native_list(f1 bigserial not null,f2 ...
CREATE FUNCTION and PL/SQL User's Guide and ReferenceASC | DESCUse ASC or DESC to indicate whether the index should be created in ascending or descending order. Indexes on character data are created in ascending or descending order of the character values in the database character set.Oracle...