SQL 92 标准

        项目终于结束了，总结的时候到了... hehe :)

        在项目中我们遇到了很多的问题，标准SQL使用就是其中一个。 因为我们在做BI package的时候，一开始都是基于MS SQL 来做的，所以Universe的设计上也没有太多的考虑。 当后来老大告诉我偶们要同时release 一个基于 Oracle 的版本时，我们才发现问题来了。 因为在Universe里面我们使用的SQL很多都不是标准的SQL，很多都是MSSQL所独有的，也就是 T-SQL(Transcate SQL)， 所以当把universe移植到Oracle上的时候，我们不得不为Oracle重新做了一套Universe。又因为Dashboard和Crystal Reports都是基于Universe来做的，所以最后我们的efforts 被扩大了一倍 ... 杯具啊！！

        项目做完了，现在来研究下哪些SQL是通用的，防止以后不要犯同样的错误。  以下内容均为本人google 所得，转载喽~~   hehe~

 

【概念总结】

1. 基本应用上，sql server 和oracle都遵循sql 92语法标准。
2. 实际应用中大家都会超出以上标准，使用各家数据库厂商都提供的丰富的自定义标准函数库和语法。
3. 微软sql server的sql 扩展叫T-SQL(Transcate SQL).
4. Oracle 的sql 扩展叫PL-SQL.
5. 最简单的插入、删除操作都差不多，但是稍微复杂一点，都不一样了。比如涉及到跨数据表，跨数据库，跨用户的操作的语法不一样。
6. 一个很简单的例子，去数据库系统时间的写法
tsql: select getdate()
pl-sql: select sysdate from dual

 

【SQL 92国际标准】

1. HOWTO - SQL92 Syntax

    - http://owen.sj.ca.us/rkowen/howto/sql92F.html

 

2. Wikipedia

    - http://en.wikipedia.org/wiki/SQL-92

    - http://en.wikipedia.org/wiki/SQL

 

 

【前人总结】

1. Oracle与SQL Server的几点不同

    - http://www.programfan.com/blog/article.asp?id=9101

 

2. SQL 92语法标准

以下内容来自CSDN博客，转载请标明出处：http://blog.csdn.net/wnhoo/archive/2007/04/11/1560941.aspx

==================================================
SQL92 Syntax and common or <Oracle> additions (not = '!')

数据类型: 
    CHAR(n) | CHARACTER(n)
    VARCHAR(n) | CHARACTER VARYING(n) | <VARCHAR2(n)>
    INTEGER | INT | SMALLINT
    DECIMAL(p,s) | DEC(p,s) | NUMERIC(p,s)
    FLOAT(p) | REAL | DOUBLE PRECISION
    DATE | TIME
    INTERVAL year-month | INTERVAL day
    BOOLEAN | BLOB
 
 条件: 
    < > <= >= <> =            AND OR NOT
    IS [NOT] NULL            [NOT] LIKE
    [NOT] IN ( [,...] )        [NOT] BETWEEN x AND y
    [conditional] ANY ( [,...] )
    [conditional] ALL ( [,...] )
 
 函数: 
    AVG | MAX | MIN | SUM | COUNT
    GREATEST|LEAST(x,y,...)
    <{ROUND|TRUNC<!ATE>}({x,places|date,format})>
    POSITION( s1 IN s2)
    EXTRACT( datetime FROM datetime_value)
    CHAR_LENGTH( s1 ) <LENGTH( s1 )>
    SUBSTRING(string FROM start [FOR length])|<SUBSTR(string,start,length)>
    <INSTR(str,substr,start,mnth)>
    {<INITCAP>|UPPER|LOWER}(string)
    TRIM({BOTH|LEADING|TRAILING} char FROM string)|<{L|R}TRIM(str,chrset)>
    {TRANSLATE|CONVERT}( char USING value) |<TRANSLATE(str,from,to)>
    <{L|R}PAD(str,to_len,str2)>
    <DECODE(expr,search1,result1,...[,default])>
    <NVL(expr,replace)>
  
 <Date Format - ROUND|TRUNC|TO_CHAR|TO_DATE(value,fmt)>: 
    SYYYY|YYYY|YEAR|SYEAR|YY|IYYY|RR|RRRR        MONTH|MON|MM|RM
    DDD|DD|J    DAY|DY|D    HH|HH12|HH24    MI    SS|SSSSS
    IW  AM|PM  BC Q WW(year week) W (month week)
 
 Table 约束: 
    [CONSTRAINT cname] {{UNIQUE|PRIMARY KEY}(col,...)|
    CHECK(condition)|FOREIGN KEY (col,...) REFERENCES table(col,...)}
 
 Column 约束: 
    [CONSTRAINT cname] {[NOT] NULL|UNIQUE|PRIMARY KEY|
    REFERENCES table(col,...) ON DELETE CASCADE|CHECK(condition)}
 
===================================================
数据库命令

ALTER TABLE 
Description: 修改table结构
    ALTER TABLE table [ * ]
        ADD [<!COLUMN>] column type
    ALTER TABLE table [ * ]
        DROP [ COLUMN ] column
    ALTER TABLE table [ * ]
        MODIFY [<!COLUMN>] column { <!SET> DEFAULT value | DROP DEFAULT }
    ALTER TABLE table [ * ]
        MODIFY [<!COLUMN>] column column_constraint
    ALTER TABLE table [ * ]
        RENAME [<!COLUMN>] column TO newcolumn
    ALTER TABLE table
        RENAME TO newtable
    ALTER TABLE table
        ADD table_constraint
    ALTER TABLE table
        {ENABLE|DISABLE} {NO}VALIDATE CONSTRAINT constraint
 
ALTER USER 
Description: 设置用户密码
    ALTER USER username IDENTIFIED BY passwd
 
CREATE TABLE 
Description: Creates a new table 
    CREATE <![TEMPORARY|TEMP]> TABLE table (
        column type
        [ NULL | NOT NULL ] [ UNIQUE ] [ DEFAULT value ]
        [column_constraint_clause | PRIMARY KEY } [ ... ] ]
        [, ... ]
        [, PRIMARY KEY ( column [, ...] ) ]
        [, CHECK ( condition ) ]
        [, table constraint ]
        )
    <CREATE TABLE table AS select query>
 
(CREATE <OR REPLACE> TRIGGER)  (非SQL92语法) 
Description: Creates a new trigger 
    CREATE TRIGGER name { BEFORE | AFTER |INSTEAD OF}
        {DELETE| INSERT | UPDATE [OF (col,...)] [OR ...] }
        ON {table|view} FOR EACH { ROW | STATEMENT }
        [ WHEN (condition) ]
        [<!EXECUTE PROCEDURE func ( arguments )>| pl/sql block]
 
CREATE SEQUENCE  (非SQL92语法) 
Description: 创建一个序号生成器
    CREATE SEQUENCE seqname [ INCREMENT BY increment ]
        [ MINVALUE minvalue ] [ MAXVALUE maxvalue ]
        [ START start ] [ CACHE cache | <WITH> NOCACHE ] [ CYCLE ]

    (use seqname.CURRVAL & seqname.NEXTVAL)
 
CREATE INDEX  (非SQL92语法)  
Description: Constructs a secondary index 
    CREATE [UNIQUE|<BITMAP>] INDEX index_name ON table
        [<!USING acc_name>] ( column [ASC|DESC][,...]) [NOSORT|REVERSE]
    CREATE [ UNIQUE ] INDEX index_name ON tabl
4000
e
        [ USING acc_name ] ( func_name( column [, ... ]) [ ops_name ] )
 
(CREATE <OR REPLACE> VIEW) 
Description: Constructs a virtual table 
    CREATE VIEW view AS select query
    ALTER VIEW view COMPILE
 
CREATE SYNONYM   (非SQL92语法)   
Description: 创建一个对象的别名 
    CREATE SYNONYM synname FOR object
 
COMMENT  (Oracle) 
Description: Comment on objects and view in USER_{TAB|COL}_COMMENTS 
    COMMENT ON TABLE table IS 'string'
    COMMENT ON COLUMN table.col IS 'string'
 
TRUNCATE TABLE   (Oracle) 
Description: Remove all table rows
    TRUNCATE TABLE table
 
RENAME TABLE  (Oracle) 
Description: Rename the object 
    RENAME table TO newtable
 
DROP 
Description: Removes existing objects from database 
    DROP TABLE name [,...] <CASCADE CONSTRAINTS>
    DROP VIEW name
    DROP SEQUENCE name [,...]
    ...

-------------------------------------------------------------------------------
INSERT 
Description: Inserts new rows into a table 
    INSERT INTO table [ ( column [, ...] ) ]
        { VALUES ( expression [, ...] ) | SELECT query }
 
UPDATE 
Description: Replaces values of columns in a table 
    UPDATE table SET col = expression [,...]
        [ FROM fromlist ]
        [ WHERE condition ]
 
DELETE 
Description: Removes rows from a table 
    DELETE FROM table [ WHERE condition ]
 
SELECT query 
Description: Retrieve rows from a table or view 
    SELECT [ ALL | DISTINCT [ ON ( expression [, ...] ) ] ]
        expression [ <![AS]> name ] [,...]
        [ INTO [ TEMPORARY | TEMP ] [ TABLE ] new_table ]
        [ FROM {table | (select query)} [ alias ] [,...] ]
        [ {{LEFT | RIGHT} [OUTER] | NATURAL |[FULL] OUTER} JOIN table alias
        {ON condition | USING(col1,col2,...)} ]
        [ WHERE {condition | EXISTS (correlated subquery)} ]
        [ GROUP BY column [,...] ]
        [ HAVING condition [,...] ]
        [ { UNION [ ALL ] | INTERSECT | EXCEPT | MINUS } select ]
        [ ORDER BY {column | int} [ ASC | DESC | USING operator ] [,...] ]
        [ FOR UPDATE [ OF class_name [,...] ] ]
        LIMIT { count | ALL } [ { OFFSET | ,} start ]
 
DECLARE  (Oracle) 
Description: Defines a cursor for table access
    DECLARE cursorname [ BINARY ] [ INSENSITIVE ] [ SCROLL ]
        CURSOR FOR query
        [ FOR { READ ONLY | UPDATE [ OF column [,...] ] ]
 
FETCH  (Oracle) 
Description: Gets rows using a cursor 
    FETCH [ selector ] [ count ] { IN | FROM } cursor
    FETCH [ RELATIVE ] [{ [ # | ALL | NEXT | PRIOR ] }] FROM cursor
 
Command: CLOSE  (Oracle) 
Description: Close a cursor 
    CLOSE cursor