SELECT first_name, last_name FROM student_details; You can also use clauses like WHERE, GROUP BY, HAVING, ORDER BY with SELECT statement. We will discuss these commands in coming chapters. NOTE: In a SQL SELECT statement only SELECT and FROM statements are mandatory. Other clauses like ...
SQL命令 SELECT(四) WHERE子句 WHERE子句限定或取消查询选择中的特定行。 符合条件的行是那些条件表达式为真的行。 条件表达式是逻辑测试(谓词)的列表,可以通过AND和OR逻辑操作符链接这些测试(谓词)。 这些谓词可以使用NOT一元逻辑操作符进行反转。 SQL谓词可分为以下几类: ...
Note:TheSELECT INTOstatement creates a new table. If the database already has a table with the same name,SELECT INTOgives an error. If you want to copy data to an existing table (rather than creating a new table), you should use theINSERT INTO SELECTstatement. Copy Selected Columns Only ...
数据查询语言(DQL,Data Query Language):用于从表中获得数据,关键字是SELECT 实际应用中,我们通常是编写SQL语句,提交给数据库或大数据系统来执行,然后获取执行结果;有几个容易搞迷糊的概念如下: Statement:语句,通常指整个SQL文本 Clause:子句,通常指SQL文本中的一部分,如From子句、Where子句、Group By子句 Query:查询...
BasicSELECTstatement基本的select语句 The basicsyntax for aSELECT statement is presented below. SELECT语句的基本语法如下。 |:多选一 []:可选择的内容 {}:多选一 没有被{}括起来的是必选 SELECT [DISTINCT |ALL] {* | select_list} FROM {table_name [alias] | view_name} ...
SQL SELECT INTO Examples The following SQL statement creates a backup copy of Customers: SELECT*INTOCustomersBackup2017 FROMCustomers; The following SQL statement uses theINclause to copy the table into a new table in another database: SELECT*INTOCustomersBackup2017IN'Backup.mdb' ...
SELECT lastName, firstName FROM employees;Code language: SQL (Structured Query Language) (sql) Using the SQL SELECT statement with other elements Besides the table columns, you can use the following elements in the SELECT clause: Strings or Numbers Expressions SQL functions User-defined function. ...
TheSELECTstatement is used to select data from a database. ExampleGet your own SQL Server Return data from the Customers table: SELECTCustomerName, CityFROMCustomers; Try it Yourself » Syntax SELECTcolumn1,column2, ... FROMtable_name; ...
INSERT INTO SELECT Syntax The syntax of the SQLINSERT INTO SELECTstatement is: INSERTINTOdestination_table (column1, column2, column3, ...)SELECTcolumn1, column2, column3, ...FROMsource_table; Here, destination_tableis the name of the table where the data is to be inserted ...
(SELECT INDEX_NAME FROM T3 WHERE T3.TABLESPACE_NAME= T2.TABLESPACE_NAME); 311 rows selected. Execution Plan --- 0 SELECT STATEMENT Optimizer=CHOOSE(Cost=12 Card=668 Bytes=62124) 1 0 HASH JOIN (SEMI) (Cost=12 Card=668 Bytes=62124) 2 1 HASHJOIN (Cost=9 Card=668 Bytes=39412) 3 ...