SELECT* FROMdepartments; 从departments表中选择所有的行rows. 每个行要显示所有列column. Selecting Specific Columns: SELECTdepartment_id, location_id FROMdepartments; 从departments表中选择指定行. Write SQL Statements Chose the statem
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; ...
You can rename the columns that result from your select statements. To do this use the AS statement like so: SELECT LastName as SirName FROM Person.Person This displays the result as “SirName” rather than “LastName.” This is a nice feature from a vanity point of view, but it also...
[CHARACTER SET charset_name]export_options|INTODUMPFILE'file_name'|INTOvar_name[, var_name]][FOR {UPDATE | SHARE} [OF tbl_name [, tbl_name]...][NOWAIT | SKIP LOCKED]|LOCKINSHARE MODE]]SELECTisusedtoretrieve rows selectedfromoneormore tables,andcan includeUNIONstatementsandsubqueries. See...
DML statements and CREATE TABLE ... AS SELECT statements that reference remote objects can run in parallel. However, the "remote object" must really be on a remote database. The reference cannot loop back to an object on the local database (for example, by way of a synonym on the remot...
To perform this operation, the Microsoft Jet database engine searches the specified table or tables, extracts the chosen columns, selects rows that meet the criterion, and sorts or groups the resulting rows into the order specified. SELECT statements do not change data in the da...
SELECT Statement,Frozen,Frozen_Different,STATEMENT_LOCATIONS->Location AS Routine,STATEMENT_LOCATIONS->Type AS RoutineType FROM INFORMATION_SCHEMA.STATEMENTS WHERE Frozen=1 OR Frozen=2 以下示例返回当前命名空间中包含COUNT(*)聚合函数的所有SQL语句。(请注意,指定语句文本(COUNT(*))时必须使用与SQL语句文本相同...
modified or deleted. The process of identifying these rows is the same process used to identify the source rows that contribute to the result set of a SELECT statement. The UPDATE and INSERT statements may both contain embedded SELECT statements that provide the data values to be updated or ...
S. Use UNION of three SELECT statements to show the effects of ALL and parentheses The following examples useUNIONto combine the results of three tables that all have the same five rows of data. The first example usesUNION ALLto show the duplicated records, and returns all 15 rows. The se...
For example, the following statements are not allowed: ALTER TABLE t1 DROP COLUMN f1 DROP (f2); ALTER TABLE t1 DROP COLUMN f1 SET UNUSED (f2); ALTER TABLE t1 DROP (f1) ADD (f2 NUMBER); ALTER TABLE t1 SET UNUSED (f3) ADD (CONSTRAINT ck1 CHECK (f2 > 0)); You can drop an ...