MySQL |
SQL SERVER |
CHAR_LENGTH(str) |
LEN(character_expression) |
CONCAT(str1,str2,...) |
str1+str2 |
INSERT(str,pos,len,newstr) |
STUFF ( character_expression , start , length ,character_expression ) |
LOCATE(substr,str [,pos]) |
CHARINDEX ( expression1 ,expression2 [ , start_location ] ) |
LEFT(str,len) |
LEFT ( character_expression , integer_expression ) |
LENGTH(str) |
DATALENGTH ( expression ) |
LTRIM(str) |
LTRIM(character expression) |
REPEAT(str,count) |
REPLICATE(character_expression,times) |
REPLACE(str,from_str,to_str) |
REPLACE(character_expression,searchstring,replacementstring) |
REVERSE(str) |
REVERSE(character_expression) |
RIGHT(str,len) |
RIGHT(character_expression,integer_expression) |
RTRIM(str) |
RTRIM(character expression) |
|
SUBSTRING(str,pos,len) |
SUBSTRING(character_expression, position, length) |
|
SUBSTRING_INDEX(str,delim,count) |
无 |
|
TRIM([{BOTH | LEADING | TRAILING} [remstr] FROM] str) |
无 |
MySQL |
SQL SERVER |
CURDATE() |
无 |
CURTIME() |
无 |
DATE(expr) |
无 |
|
DATE_ADD(date,INTERVAL expr unit) |
DATEADD(datepart, number, date) |
|
DAY(date) |
DATEPART('dd', date) |
|
HOUR(time) |
DATEPART('hh', date) |
|
MINUTE(time) |
DATEPART('mi', date) |
|
MONTH(date) |
DATEPART('mm', date) |
|
NOW() |
GETDATE() |
|
SECOND(time) |
DATEPART('ss', date) |
|
TIME(expr) |
无 |
|
YEAR(date) |
DATEPART('yy', date) |
v在创建视图时需要注意：
如果表Test中有A、B两个字段，创建视图如下
Create view v_test as select * from Test;
此时视图实际的定义如下：
Create view v_test as select A,B from Test;
也就是说Test将来增加的字段并不在视图里面。
在SQL SERVER中，如果创建视图如下
Create view v_test as select * from Test;
此时视图实际的定义就是：
Create view v_test as select * from Test;
视图中永远都包含Test的所有字段。