db2常用傻瓜問(wèn)題1000問(wèn)(之四)
作者: ccbzzp
大家在應(yīng)用db2的時(shí)候可能會(huì)遇到一些看似簡(jiǎn)單的問(wèn)題,特別對(duì)新手來(lái)說(shuō),我在此簡(jiǎn)單的總結(jié)一下,發(fā)布給大家,希望對(duì)大家能有所幫助,同時(shí)也歡迎大家一起探討,共同發(fā)展,共同進(jìn)步!
以下主要以db2 7.x為基礎(chǔ)的. 以下的字符為小寫(xiě).
本文對(duì)db2高手來(lái)說(shuō)是不用看的.
db2函數(shù)
135. avg()
返回一組數(shù)值的平均值.
select avg(salary) from bsempms;
136. corr(),correlation()
返回一對(duì)數(shù)值的關(guān)系系數(shù).
select correlation(salary,bonus) from bsempms;
137. count()
返回一組行或值的個(gè)數(shù).
select count(*) from bsempms;
138. covar(),covariance()
返回一對(duì)數(shù)值的協(xié)方差.
select covar(salary,bonus) from bsempms;
139. max()
返回一組數(shù)值中的最大值.
select max(salary) from bsempms;
140. min()
返回一組數(shù)值中的最小值.
select min(salary) from bsempms;
141. stddev()
返回一組數(shù)值的標(biāo)準(zhǔn)偏差.
select stddev(salary) from bsempms;
142. sum()
返回一組數(shù)據(jù)的和.
select sum(salary) from bsempms;
143. var(),variance()
返回一組數(shù)值的方差.
select variance(salary) from bsempms;
144. abs(),absval()
返回參數(shù)的絕對(duì)值.
select abs(-3.4) from bsempms;
145. acos()
返回參數(shù)的反余弦值.
select acos(0.9) from bsempms;
146. ascii()
返回整數(shù)參數(shù)最左邊的字符的ascii碼.
select ascii('r') from bsempms;
147. asin()
返回用弧度表示的角度的參數(shù)的反正弦函數(shù).
select asin(0.9) from bsempms;
148. atan()
返回參數(shù)的反正切值,該參數(shù)用弧度表示的角度的參數(shù).
select atan(0.9) from bsempms;
149. atan2()
返回用弧度表示的角度的x和y坐標(biāo)的反正切值.
select atan2(0.5,0.9) from bsempms;
150. bigint()
返回整型常量中的數(shù)字或字符串的64位整數(shù)表示.
select bigint(emp_no) from bsempms;
151. ceiling() or ceil()
返回比參數(shù)大或等于參數(shù)的最小的整數(shù)值.
select ceiling(3.56) from bsempms;
select ceil(4.67) from bsempms;
152. char()
返回日期時(shí)間型,字符串,整數(shù),十進(jìn)制或雙精度浮點(diǎn)數(shù)的字符串表示.
select char(salary,',') from bsempms;
153. chr()
返回具有由參數(shù)指定的ascii碼的字符.
select char(167) from bsempms;
154. concat()
返回兩個(gè)字符串的連接.
select concat(emp_no,emp_nam) from bsempms;
155. year()
返回?cái)?shù)值的年部分.
select year('2003/01/02') from bsempms;
156. varchar()
返回字符串,日期型,圖形串的可變長(zhǎng)度的字符串表示.
select varchar(emp_nam,50) from bsempms;
157. ucase() or upper()
返回字符串的大寫(xiě).
select ucase(emp_nam) from bsempms;
select upper(emp_no) from bsempms;
158. truncate() or trunc()
從表達(dá)式小數(shù)點(diǎn)右邊的位置開(kāi)始截?cái)鄟K返回該數(shù)值.
select truncate(345.6789,2) from bsempms;
159. time()
返回一個(gè)數(shù)值中的時(shí)間.
select time('2001-03-19.12.30.123456') from bsempms;
160. substr(exp1,exp2)
返回exp1串自exp2處開(kāi)始的子串.
select substr('cdnjfdjfjd',5) from bsempms;
select substr('cdnjfdjfjd',5,2) from bsempms;
161. sqrt()
返回該參數(shù)的平方根.
select sqrt(36) from bsempms;
162. space()
返回由參數(shù)指定的長(zhǎng)度,包含空格在內(nèi)的字符串.
select space(10) from bsempms;
163. second()
返回一個(gè)數(shù)值的秒部分.
select second('18:34:32') from bsempms;
164. rtrim()
刪除字符串尾部的空格.
select rtrim('comment ') from bsempms;
165. round(exp1,exp2)
返回exp1小數(shù)點(diǎn)右邊的第exp2位置處開(kāi)始的四舍五入值.
select round(2345.6789,2) from bsempms;
166. replace(exp1,exp2,exp3)
用exp3替代exp1中所有的exp2
select char(replace('romandd','ndd','ccb'),10) from bsempms;
167. repeat(exp1,exp2)
返回exp1重復(fù)exp2次后的字符串.
select char(repeat('repeat',3),21) from bsempms;
168. real()
返回一個(gè)數(shù)值的單精度浮點(diǎn)數(shù)表示.
select real(10) from bsempms;
169. rand()
返回0和1之間的隨機(jī)浮點(diǎn)數(shù).
select rand() from bsempms;
170. power(exp1,exp2)
返回exp1的exp2次冪.
select power(2,5) from bsempms;
171. posstr(exp1,exp2)
返回exp2在exp1中的位置.
select ('abcdefgh','d') from bsempms;
172. nullif(exp1,exp2)
如果exp1=exp2,則為null,否則為exp1
173. nodenumber()
返回行的分區(qū)號(hào).
select nodenumber(emp_no) from bsempms;
174. month()
返回一個(gè)數(shù)值的月部分.
select month('2003/10/20') from bsempms;
175. mod(exp1,exp2)
返回exp1除以exp2的余數(shù).
select mod(20,8) from bsempms;
176. minute()
返回一個(gè)數(shù)值的分鐘部分.
select minute('18:34:23') from bsempms;
177. ltrim()
刪除字符串前面的空格.
select ltrim(' cddd') from bsempms;
178. hour()
返回一個(gè)數(shù)值的小時(shí)部分.
select hour('18:34:23') from bsempms;
179. double()
如果參數(shù)是一個(gè)數(shù)字表達(dá)式,返回與其相對(duì)應(yīng)的浮點(diǎn)數(shù),如果參數(shù)是字符串表達(dá)式,則返回該數(shù)的字符串表達(dá)式.
select double('5678') from bsempms;
180. exp()
返回參數(shù)的指數(shù)函數(shù).
select exp(2) from bsempms;
181. float()
返回一個(gè)數(shù)的浮點(diǎn)表示.
select float(789) from bsempms;
182. floor()
返回小于或等于參數(shù)的最大整數(shù).
select floor(88.93) from bsempms;
183. hex()
返回一個(gè)表示為字符串的值的16進(jìn)制表示.
select hex(16) from bsempms;
待續(xù)...
