以前一直用mssql 做开发，最近的项目都Oracle，T-SQL与PL/SQL比较下怎么样呢，从网上搜索下相关的资料，整理如下：
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 |
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记录 |
Record |
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表字段 |
%type |
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表记录 |
%rowtype |
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表 |
Table |
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自动增长变量 |
AUTOINCREMENT |
2)变量声明、赋值与引用
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TSQL |
PL/SQL |
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声明 |
declare @ls_casher char(1), @ln_payAmt decimal(14,4) |
declare on_hand INTEGER; ls_casher char(1); |
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赋值 |
select @ls_casher = 'A' |
ls_casher:=’A’; |
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引用 |
if @ ls_casher = 'A' … |
if ls_casher = 'A' then … |
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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; |
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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 |
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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 |
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系统日期 |
getdate() |
SYSDATE |
空值判断与处理
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TSQL |
PL/SQL |
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判断 |
IS NULL |
IS NULL |
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空值替换 |
Isnull(para,0) |
NVL(para,0) REPLACE(old_string, NULL, my_string) |
转换
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TSQL |
PL/SQL |
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字符->日期 |
Convert(datetime, expr, style) |
To_Date(format, expr) |
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字符<-日期、数值 |
Convert(char(n), expr, style) |
To_char(expr,format) |
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数值 |
To_Number() |
语句
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TSQL |
PL/SQL |
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statement block |
BEGIN...END |
BEGIN...END; |
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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 |
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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; |
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GOTO |
GOTO label … label: … |
GOTO label; … <<label>> … |
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Exits unconditionally |
RETURN |
Return; |
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Sets a delay for statement execution |
WAITFOR |
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Comment |
-- /*…*/ |
-- /*…*/ |
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PRINT string |
Set serveroutput on dbms_output.put_line(string); |
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RAISERROR |
RAISERROR |
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EXECUTE |
EXECUTE |
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NULL statement |
NULL; |
4)cursor
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TSQL |
PL/SQL |
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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; |
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open |
Open cursor_name |
Open cursor_name; |
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Fetch |
Fetch cursor_name into var1,var2… |
Fetch cursor_name into var1,var2… || %rowtype_var; |
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Close |
Close cursor_name |
Close cursor_name; |
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Attribute |
@@FETCH_STATUS @@CURSOR_ROWS CURSOR_STATUS |
%found %notfound %isopen %rowcount |
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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 |
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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] … |
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类型(按触发级别和时序) |
语句 after |
行或语句 before or after |
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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 |
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谓词/函数/属性 |
Inserting、updating、deleteing Updating(col) |
Update(col) |
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使能 |
Alter table tabname {disable|enable} trigger {t_name|all} |
Alter trigger t_name {disable|enable} |
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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 |
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删除 |
Drop trigger t_name |
Drop trigger t_name; |
6)procedure
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TSQL |
PL/SQL |
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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} … |
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查询 |
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删除 |
DROP PROCEDURE p_name |
DROP PROCEDURE p_name; |
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调用 |
EXEC p_name [para1[,…]] |
P_name[(para1[,…])]; |
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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 |
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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 |
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对象脚本 |
sp_helptext |
DESC、ALL_source |
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用户表 |
Sysusers |
All_users |
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表列 |
All_tab_columns |
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依赖 |
All_dependencies |
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字典表说明 |
DICT |
8)SQL
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TSQL |
PL/SQL |
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Select |
Select @var=<value> |
Select value into var from dual |
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Insert |
insert / insert into |
insert into |
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Delete |
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比较 |
Any, some, all |
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集合 |
Union、Union all、Intersect、Minus、 |
9)全局变量
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TSQL |
PL/SQL |
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语句执行成功 |
error |
SQLCODE |
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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 |
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读取、执行SQL文件 |
Isql –Usa –Ppass –Shost –ifile |
sqlplus [-s] user/pass@db -@filename |
11) 杂项
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TSQL |
PL/SQL |
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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 |
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保留点 |
¨ Save transcation Sp_name ¨ ROLLBACK TRANSACTION percentchanged |
¨ Savepoint Sp_name ¨ Rollback to savepoint sp_name |
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对模式对象改名 |
Rename |
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分析对象 |
Analyze |
Sp_help? |
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
)
其他文章
Oracle语句总结 http://www.cnblogs.com/and/archive/2010/04/11/1709589.html
Oracl 10G与sql server2005搜索运行时间测试
发现了oracle 与mssql互转的工具http://www.convert-in.com/ora2mss.htm 可惜这个是收费的
推荐《Microsoft SQL Server 2005技术内幕》三本、《Oracle PL/SQL程序设计（第5版）》