1.×Ö·û´®º¯Êý
³¤¶ÈÓë·ÖÎöÓÃ
datalength(Char_expr) ·µ»Ø×Ö·û´®°üº¬×Ö·ûÊý,µ«²»°üº¬ºóÃæµÄ¿Õ¸ñ
substring(expression,start,length) ²»¶à˵ÁË,È¡×Ó´®
right(char_expr,int_expr) ·µ»Ø×Ö·û´®ÓÒ±ßint_expr¸ö×Ö·û
×Ö·û²Ù×÷Àà
upper(char_expr) תΪ´óд
lower(char_expr) תΪСд
space(int_expr) Éú³Éint_expr¸ö¿Õ¸ñ
replicate(char_expr,int_expr)¸´ÖÆ×Ö·û´®int_expr´Î
reverse(char_expr) ·´×ª×Ö·û´®
stuff(char_expr1,start,length,char_expr2) ½«×Ö·û´®char_expr1ÖеĴÓ
start¿ªÊ¼µÄlength¸ö×Ö·ûÓÃchar_expr2´úÌæ
ltrim(char_expr) rtrim(char_expr) È¡µô¿Õ¸ñ
ascii(char) char(ascii) Á½º¯Êý¶ÔÓ¦,È¡asciiÂë,¸ù¾ÝasciiÂðÈ¡×Ö·û
×Ö·û´®²éÕÒ
charindex(char_expr,expression) ·µ»Øchar_exprµÄÆðʼλÖÃ
patindex("%pattern%",expression) ·µ»ØÖ¸¶¨Ä£Ê½µÄÆðʼλÖÃ,·ñÔòΪ0
2.Êýѧº¯Êý
abs(numeric_expr) Çó¾ø¶ÔÖµ
ceiling(numeric_expr) È¡´óÓÚµÈÓÚÖ¸¶¨ÖµµÄ×îСÕûÊý
exp(float_expr) È¡Ö¸Êý
floor(numeric_expr) СÓÚµÈÓÚÖ¸¶¨ÖµµÃ×î´óÕûÊý
pi() 3.1415926.........
power(numeric_expr,power) ·µ»Øpower´Î·½
rand([int_expr]) Ëæ»úÊý²úÉúÆ÷
round(numeric_expr,int_expr) °²int_expr¹æ¶¨µÄ¾«¶ÈËÄÉáÎåÈë
sign(int_expr) ¸ù¾ÝÕýÊý,0,¸ºÊý,,·µ»Ø+1,0,-1
sqrt(float_expr) ƽ·½¸ù
////////////////////////////////////////////////////////////////////
Ò»¡¢×Ö·ûת»»º¯Êý
1¡¢ASCII()
·µ»Ø×Ö·û±í´ïʽ×î×ó¶Ë×Ö·ûµÄASCII ÂëÖµ¡£ÔÚASCII£¨£©º¯ÊýÖУ¬´¿Êý×ÖµÄ×Ö·û´®¿É²»ÓÑ’À¨ÆðÀ´£¬µ«º¬ÆäËü×Ö·ûµÄ×Ö·û´®±ØÐëÓÑ’À¨ÆðÀ´Ê¹Ó㬷ñÔò»á³ö´í¡£
2¡¢CHAR()
½«ASCII Âëת»»Îª×Ö·û¡£Èç¹ûûÓÐÊäÈë0 ~ 255 Ö®¼äµÄASCII ÂëÖµ£¬CHAR£¨£© ·µ»ØNULL ¡£
3¡¢LOWER()ºÍUPPER()
LOWER()½«×Ö·û´®È«²¿×ªÎªÐ¡Ð´£»UPPER()½«×Ö·û´®È«²¿×ªÎª´óд¡£
4¡¢STR()
°ÑÊýÖµÐÍÊý¾Ýת»»Îª×Ö·ûÐÍÊý¾Ý¡£
STR (<float_expression>[£¬length[£¬ <decimal>]])
length Ö¸¶¨·µ»ØµÄ×Ö·û´®µÄ³¤¶È£¬decimal Ö¸¶¨·µ»ØµÄСÊýλÊý¡£Èç¹ûûÓÐÖ¸¶¨³¤¶È£¬È±Ê¡µÄlength ֵΪ10£¬ decimal ȱʡֵΪ0¡£
µ±length »òÕßdecimal Ϊ¸ºÖµÊ±£¬·µ»ØNULL£»
µ±length СÓÚСÊýµã×ó±ß£¨°üÀ¨·ûºÅ룩µÄλÊýʱ£¬·µ»Ølength ¸ö*£»
ÏÈ·þ´Ólength £¬ÔÙÈ¡decimal £»
µ±·µ»ØµÄ×Ö·û´®Î»ÊýСÓÚlength £¬×ó±ß²¹×ã¿Õ¸ñ¡£
¶þ¡¢È¥¿Õ¸ñº¯Êý
1¡¢LTRIM() °Ñ×