介紹一下TSQL與PL/SQL的區別
1)數據類型
TSQL | PL/SQL | |
numeric(p,s) | numeric(p,s) or NUMBER(p,s) | |
decimal(p,s) | decimal(p,s) or NUMBER(p,s) | |
char(m) | Char(m) | |
varchar(m) | varchar2(m) | |
datetime | date | |
記錄 | Record | |
表字段 | %type | |
表記錄 | %rowtype | |
表 | Table | |
自動增長變量 | AUTOINCREMENT |
2)變量聲明、賦值與引用
TSQL | PL/SQL | |
聲明 | declare @ls_casher char(1), @ln_payAmt decimal(14,4) | declare on_hand INTEGER; ls_casher char(1); |
賦值 | select @ls_casher = 'A' | ls_casher:=’A’; |
引用 | if @ ls_casher = 'A' … | if ls_casher = 'A' then … |
在SQL語句中賦值 | SELECT @ls_casher=sal FROM emp WHERE empno = emp_id; | SELECT sal INTO ls_casher FROM emp WHERE empno = emp_id; |
在SQL語句中引用 | SELECT * FROM emp WHERE sal = @ls_casher; | SELECT * FROM emp WHERE sal = ls_casher; |
3)函數與操作符
字符串
TSQL | PL/SQL | |
連接 | + | || |
TRIM | LTRIM、RTRIM | |
SUBSTRING | SUBSTR、SUBSTRB | |
INSTR、INSTRB | ||
right(str,n) | substr(str,-n) |
日期
TSQL | PL/SQL | |
系統日期 | getdate() | SYSDATE |
空值判斷與處理
TSQL | PL/SQL | |
判斷 | IS NULL | IS NULL |
空值替換 | Isnull(para,0) | NVL(para,0) REPLACE(old_string, NULL, my_string)
|
轉換
TSQL | PL/SQL | |
字符->日期 | Convert(datetime, expr, style) | To_Date(format, expr) |
字符<-日期、數值 | Convert(char(n), expr, style) | To_char(expr,format) |
數值 | To_Number() |
語句
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 | |
Comment | -- /*…*/ | -- /*…*/ |
PRINT string | Set serveroutput on dbms_output.put_line(string); | |
RAISERROR | RAISERROR | |
EXECUTE | EXECUTE | |
NULL statement | NULL; |
4)cursor
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 | |
隱式cursor | Select…into (僅可處理單行記錄) | |
5)trigger
TSQL | PL/SQL | |
創建 | 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] … |
類型(按觸發級別和時序) | 語句 after | 行或語句 before or after |
訪問數據操縱行的值 | 通過表Inserted、Deleted訪問 | 通過記錄 :New、 :Old訪問,僅可用於行級觸發器 |
謂詞/函數/屬性 | 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 | 作爲觸發語句的一部分,不可用事務控制命令 不能聲明和使用LONG、LONG RAW變量和列 | |
刪除 | Drop trigger t_name | Drop trigger t_name; |
6)procedure
TSQL | PL/SQL | |
創建 | 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} … |
查詢 | ||
刪除 | DROP PROCEDURE p_name | DROP PROCEDURE p_name; |
調用 | EXEC p_name [para1[,…]] | P_name[(para1[,…])]; |
參數 | 按位置傳遞 | 1)按位置傳遞 2)帶名傳遞 P_name(para1=>var1);
debit_account(amount => 500, acct_id => 10261); |
7)數據字典/系統表
TSQL | PL/SQL | |
系統對象表 | Dbo.sysobjects | User_source、User_objects(OBJ)、User_tables(TABS)、User_triggers、ALL_tables、All_View、All_catalog、All_objects |
對象腳本 | sp_helptext | DESC、ALL_source |
用戶表 | Sysusers | All_users |
表列 | All_tab_columns | |
依賴 | All_dependencies | |
字典表說明 | DICT |
8)SQL
TSQL | PL/SQL | |
Select | Select @var=<value>
| Select value into var from dual
|
Insert | insert / insert into | insert into |
Delete | ||
比較 | Any, some, all | |
集合 | Union、Union all、Intersect、Minus、 |
9)全局變量
TSQL | PL/SQL | |
語句執行成功 | error | SQLCODE |
select 是否有結果 | exists | select...into + SQL%FOUND |
10) 命令行查詢工具
ISQL | SQL PLUS | |
讀取、執行SQL文件 | Isql –Usa –Ppass –Shost –ifile | sqlplus [-s] user/pass@db -@filename |
11) 雜項
TSQL | PL/SQL | |
鎖 | 在SQL語句中 Insert…With tablock Insert…With Tablockx Select…for update Select…for readonly 獨立語句 set transcation isolation level to Read uncommited
| 在SQL語句中 select …for update of…;
獨立語句 lock table tabname in row share mode; lock table tabname in share exclusive mode;
|
用戶連接數 | ||
數據庫文件 | 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;
|
顯示DML執行計劃 | Show plan | Explain plan |
保留點 | ¨ Save transcation Sp_name ¨ ROLLBACK TRANSACTION percentchanged | ¨ Savepoint Sp_name ¨ Rollback to savepoint sp_name |
對模式對象改名 | Rename | |
分析對象 | Analyze | Sp_help? |
1. select into 語法
現在有表
tablea
(
cola int ,
colb varchar(20)
)
要把tablea中滿足條件(cola <100)的記錄生成新的表tableb。
在ms sqlserver 可以直接用select into語法:
select * into tableb
where cola < 100
在oracle中語法如下:
create table tableb
as
(
select * from tablea
where cola <100
)