EXISTS子句根据其内查询语句的结果集空或者非空,返回一个布尔值。 一种通俗的可以理解为:将外查询表的每一行,代入内查询作为检验,如果内查询返回的结果取非空值,则EXISTS子句返回TRUE,这一行行可作为外查询的结果行,否则不能作为结果。 分析器会先看语句的第一个词,当它发现第一个词是SELECT关键字的时候,它会...
然后再取下一行记录；重复上述过程直到外层表的记录全部遍历一次为止。
5、CONTAINS SQL, READS SQL DATA, MODIFIES SQL DATA: 指定存储过程中的SQL访问级别 CONTAINS SQL: 表示存储过程可以执行中,既不可读取 SQL 数据,也不可修改 SQL 数据。 READS SQL DATA: 表示存储过程可以执行中,可读取SQL,但不可修改 SQL 数据。 MODIFIES SQL DATA: 表示存储过程可以执行任何 SQL 语句。可以...
Some (non)-trivial examples: In Sybase we frequently use temp. tables and stored procedure when we need to get a result from many tables. For example, DB2 中的临时表可以一个SQL表示(当然这只是一种,你可以创建session的临时表): with query1 ( col1, col2, col3, ..., colN) as ( select...
EXEC SQL CONNECT TO BETA; V1 = 528671; IV = -1; EXEC SQL CALL SUMARIZE(:V1,:V2 INDICATOR :IV); Example 2: Suppose that stored procedure MYPROC exists and produces several result sets. An application might include statements like the following to access the result sets produced by MYPR...
<ssma-script-file> <create-new-project project-folder="<project-folder>" project-name="<project-name>" overwrite-if-exists="<true/false>"/> <connect-source-database server=""/> <save-project/> <close-project/> </ssma-script-file> 產品目錄的 [範例控制台腳本] 資料夾中提供由三個...
Assume that the statements in the examples are embedded in PL/I programs. Example 1: From the table DSN8A10.EMP delete the row on which the cursor C1 is currently positioned. EXEC SQL DELETE FROM DSN8A10.EMP WHERE CURRENT OF C1; Example 2: From the table DSN8A10.EMP, delete all ro...
If the name of an index is specified, the database manager reorganizes the data according to the order in the index. To maximize performance, specify an index that is often used in SQL queries. If the name of an index is not specified, and if a clustering index exists, the data will...
overwrite-if-exists選用屬性會指出是否應該覆寫現有的專案。 {boolean} project-type:選用屬性。 表示項目類型。 例如,sql-server-2019或sql-azure。 預設值為sql-server-2016。 範例: XML <create-new-projectproject-folder="<project-folder>"project-name="<project-name>"overwrite-if-exists="<true/false>...
Chapter 1. Introduction to the DB2 OLAP server 9 MS Excel, Lotus 123 Web Gateway Essbase Application Manager Essbase Ready Front-End Tools SQL Decision Support Applications Essbase Spreadsheet Add-in Objects Hyperion Integration Server Currency Conversion Hyperion Wired for OLAP DB2 Management Tools ...