TSQL与PL/SQL的比较
以前一直用mssql 做开发，最近的项目都Oracle,
1)数据类型
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| TSQL | PL/SQL |
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| numeric(p,s) | numeric(p,s) or NUMBER(p,s) |
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| decimal(p,s) | decimal(p,s) or NUMBER(p,s) |
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| char(m) | Char(m) |
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| varchar(m) | varchar2(m) |
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| datetime | date |
| 记录 |
| Record |
| 表字段 |
| %type |
| 表记录 |
| %rowtype |
| 表 |
| Table |
| 自动增长变量 | AUTOINCREMENT |
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2)变量声明、赋值与引用
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| TSQL | PL/SQL |
| 声明 | declare @ls_casher char(1), @ln_payAmt decimal(14,4) | declare on_hand INTEGER; ls_casher char(1); |
| 赋值 | select @ls_casher = 'A' | ls_casher:=’A’; |
| 引用 | if @ ls_casher = 'A' … | if ls_casher = 'A' then … |
| 在SQL语句中赋值 | SELECT @ls_casher=sal FROM emp WHERE empno = emp_id; | SELECT sal INTO ls_casher FROM emp WHERE empno = emp_id; |
| 在SQL语句中引用 | SELECT * FROM emp WHERE sal = @ls_casher; | SELECT * FROM emp WHERE sal = ls_casher; |
3)函数与操作符
字符串
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| TSQL | PL/SQL |
| 连接 | + | || |
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| TRIM | LTRIM、RTRIM |
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| SUBSTRING | SUBSTR、SUBSTRB |
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| INSTR、INSTRB |
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| right(str,n) | substr(str,-n) |
日期
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| TSQL | PL/SQL |
| 系统日期 | getdate() | SYSDATE |
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空值判断与处理
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| TSQL | PL/SQL |
| 判断 | IS NULL | IS NULL |
| 空值替换 | Isnull(para,0) | NVL(para,0) REPLACE(old_string, NULL, my_string)
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转换
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| TSQL | PL/SQL |
| 字符->日期 | Convert(datetime, expr, style) | To_Date(format, expr) |
| 字符<-日期、数值 | Convert(char(n), expr, style) | To_char(expr,format) |
| 数值 |
| To_Number() |
语句
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| TSQL | PL/SQL |
| statement block | BEGIN...END | BEGIN...END; |
| conditional | 1) IF…ELSE… 2) IF…ELSE IF…else… 3) CASE | 1)IF..then...ELSE…end if; 2)If…then… elsif…else…endif 3)decode |
| Repeat | WHILE Boolean_expression {statement_block} [BREAK] {statement_block} [CONTINUE]
| 1)Loop …exit;…end loop; 2)loop…exit when…end loop; 3)WHILE condition LOOP sequence_of_statements; EXIT WHEN boolean_expression; END LOOP; 3)for…in [reverse]…loop … end loop; |
| GOTO | GOTO label … label: … | GOTO label; … <<label>> … |
| Exits unconditionally | RETURN | Return; |
| Sets a delay for statement execution | WAITFOR |
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| Comment | -- /*…*/ | -- /*…*/ |
| | PRINT string | Set serveroutput on dbms_output.put_line(string); |
| RAISERROR | RAISERROR |
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| EXECUTE | EXECUTE |
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| NULL statement |
| NULL; |
4)cursor
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| TSQL | PL/SQL |
| DECLARE | DECLARE cursor_name CURSOR [LOCAL | GLOBAL] [FORWARD_ONLY | SCROLL] [STATIC | KEYSET | DYNAMIC | FAST_FORWARD] [READ_ONLY | SCROLL_LOCKS | OPTIMISTIC] [TYPE_WARNING] FOR select_statement [FOR UPDATE [OF column_name [,...n]]] | DECLARE CURSOR cursor_name IS SELECT_statement; |
| open | Open cursor_name | Open cursor_name; |
| Fetch | Fetch cursor_name into var1,var2… | Fetch cursor_name into var1,var2… || %rowtype_var; |
| Close | Close cursor_name | Close cursor_name; |
| Attribute | @@FETCH_STATUS @@CURSOR_ROWS CURSOR_STATUS | %found %notfound %isopen %rowcount |
| DEALLOCATE | DEALLOCATE cursor_name |
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| 隐式cursor |
| Select…into (仅可处理单行记录) |
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5)trigger
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| TSQL | PL/SQL |
| 创建 | CREATE TRIGGER trigger_name ON table [WITH ENCRYPTION] {FOR {[DELETE][,][INSERT][,] [UPDATE] } AS sql_statement [...n] } | Create or replace trigger t_name {before|after}{insert|update|delete} on table_name [for each row [when conditional] … |
| 类型(按触发级别和时序) | 语句 after | 行或语句 before or after |
| 访问数据操纵行的值 | 通过表Inserted、Deleted访问 | 通过记录 :New、 :Old访问，仅可用于行级触发器 |
| 谓词/函数/属性 | Inserting、updating、deleteing Updating(col) | Update(col) |
| 使能 | Alter table tabname {disable|enable} trigger {t_name|all} | Alter trigger t_name {disable|enable} |
| 限制 |
| 作为触发语句的一部分，不可用事务控制命令 不能声明和使用LONG、LONG RAW变量和列 |
| 删除 | Drop trigger t_name | Drop trigger t_name; |
6)procedure
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| TSQL | PL/SQL |
| 创建 | CREATE PROCEDURE] p_name [ {@parameter data_type} [VARYING] [= default] [OUTPUT] ] [,...n] [WITH { RECOMPILE | ENCRYPTION | RECOMPILE, ENCRYPTION } ] AS sql_statement [...n] | Create or replace procedure p_name [Para1 {in|out|inout} datatype[,…] [{:=|default} default_value]] {IS|AS} … |
| 查询 |
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| 删除 | DROP PROCEDURE p_name | DROP PROCEDURE p_name; |
| 调用 | EXEC p_name [para1[,…]] | P_name[(para1[,…])]; |
| 参数 | 按位置传递 | 1)按位置传递 2)带名传递 P_name(para1=>var1);
debit_account(amount => 500, acct_id => 10261); |
7)数据字典/系统表
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| TSQL | PL/SQL |
| 系统对象表 | Dbo.sysobjects | User_source、User_objects(OBJ)、User_tables(TABS)、User_triggers、ALL_tables、All_View、All_catalog、All_objects |
| 对象脚本 | sp_helptext | DESC、ALL_source |
| 用户表 | Sysusers | All_users |
| 表列 |
| All_tab_columns |
| 依赖 |
| All_dependencies |
| 字典表说明 |
| DICT |
8)SQL
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| TSQL | PL/SQL |
| Select | Select @var=<value>
| Select value into var from dual
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| Insert | insert / insert into | insert into |
| Delete |
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| 比较 |
| Any, some, all |
| 集合 |
| Union、Union all、Intersect、Minus、 |
9)全局变量
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| TSQL | PL/SQL |
| 语句执行成功 | error | SQLCODE |
| select 是否有结果 | exists | select...into + SQL%FOUND |
10) 命令行查询工具
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| ISQL | SQL PLUS |
| 读取、执行SQL文件 | Isql –Usa –Ppass –Shost –ifile | sqlplus [-s] user/pass@db -@filename |
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11) 杂项
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| TSQL | PL/SQL |
| 锁 | 在SQL语句中 Insert…With tablock Insert…With Tablockx Select…for update Select…for readonly 独立语句 set transcation isolation level to Read uncommited
| 在SQL语句中 select …for update of…;
独立语句 lock table tabname in row share mode; lock table tabname in share exclusive mode;
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| 用户连接数 |
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| 数据库文件 | Device | Tablespace
CREATE TABLESPACE testdb DATAFILE 'C:\ORANT\DATABASE\testdb.ORA' SIZE 20M AUTOEXTEND ON NEXT 2M; CREATE ROLLBACK SEGMENT "RB_TESTDB" TABLESPACE "TESTDB"; ALTER ROLLBACK SEGMENT "RB_TESTDB" ONLINE;
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| 显示DML执行计划 | Show plan | Explain plan |
| 保留点 | ¨ Save transcation Sp_name ¨ ROLLBACK TRANSACTION percentchanged | ¨ Savepoint Sp_name ¨ Rollback to savepoint sp_name |
| 对模式对象改名 | Rename |
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| 分析对象 | Analyze | Sp_help? |
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1. select into 语法
现在有表
tablea
(
cola int ,
colb varchar(20)
)
要把tablea中满足条件(cola <100)的记录生成新的表tableb。
在ms sqlserver 可以直接用select into语法：
select * into tableb
where cola < 100
在oracle中语法如下：
create table tableb
as
(
select * from tablea
where cola <100
)
离开，只为更好的活着)
