百度试题 题目SQL 语句可返回唯一不同的值的是( )。 A. SELECT ALL B. SELECT DIFFERENT C. SELECT UNIQUE D. SELECT DISTINCT 相关知识点: 试题来源: 解析 D null 反馈 收藏
是指在数据库查询中,通过使用SELECT语句来检索数据,并且只返回满足特定条件的唯一一行数据。 在数据库中,SELECT语句用于从一个或多个表中检索数据。当我们需要从表中获取特定条件下的数据时,可以...
SQL SELECT UNIQUE The SELECT UNIQUE statement is generally used in the Oracle database system to get unique values from a column of a database table. We cannot use this syntax in other RDBMS systems because SELECT UNIQUE is not an ANSI standard SQL statement. The standard ANSI SQL statements...
view, or materialized view. Oracle Database returns a set of column in the order in which the columns were specified when the object was created. A query that selects rows from two or more tables, views, or materialized views is a join. ...
MySQL的数据同步到SelectDB会进行类型转换,若您未勾选库表结构同步,则需要提前在目标SelectDB中创建好相应结构的Unique模型表。更多信息,请参见数据类型映射关系和数据模型。 源库对象 在源库对象框中单击待同步对象,然后单击将其移动至已选择对象框。同步对象的选择粒度为库、表、列。 重要 选择粒度为库级别,不支...
In the below example, we retrieve data from all columns with where condition. We use the id, name, city, and phone column to retrieve the data. After using a distinct clause on all columns with the where condition, it will retrieve the unique values from the rows we defined in the wher...
SQL Distinct So far we have used the select statement to retrieve all the records in a table regardless if some values repeat or not. If you wish, you can use the DISTINCT keyword to remove duplicates from your results. For instance if you wanted to just return a unique list of employees...
SQL Commands > Distinct In SQL, the DISTINCT keyword is used in the SELECT statement to retrieve unique values from a database table. Any value that has a duplicate will only show up once. SyntaxSELECT DISTINCT "column_name"FROM "table_name";...
Columns with an IDENTITY property that generates the values for the column. Columns that have a default that uses the NEWID function to generate a unique GUID value. Computed columns. Computed columns are virtual columns that are defined as an expression calculated from one or more other columns...
TSqlParserToken TSqlScript TSqlStatement TSqlStatementSnippet TSqlTokenType TSqlTriggerEventGroupHelper TSqlTriggerEventTypeHelper UnaryExpression UnaryExpressionType UniqueConstraintDefinition UniqueRowFilter UnpivotedTableReference UnqualifiedJoin UnqualifiedJoinType UpdateCall UpdateDeleteSpecificationBase Updat...