这个函数指判断NULL,如果字段为空字符串,则不在范围 3、NULLIF NULLIF(value1, value2) 1. 当且仅当value1等于value2时,NULLIF才返回null。否则它返回value1。 select NULLIF(address,grade),address,grade FROM student s --结果: nullif|address|grade| ---|---|---| 天河一路 |天河一路 |一年级1班...
nullif function nullifzero function nvl function nvl2 function octet_length function or operator overlay function parse_json function parse_url function percent_rank function percentile function percentile_approx function percentile_cont function percentile_disc function percentsign operator pi function pipepipe...
以下示例使用NULLIF函数将Age=20的所有记录的显示字段设置为空: SELECT Name,Age,NULLIF(Age,20) AS Nulled20 FROM Sample.Person 1. 2.
SQL FunctionComparisonTest Return Value 示例 以下示例使用NULLIF函数将Age=20的所有记录的显示字段设置为空: SELECT Name,Age,NULLIF(Age,20) AS Nulled20 FROM Sample.Person
如果exp1 = exp2, 返回null DECODE NULLIF 用户登录账号ID数字 UID SUSER_ID 用户登录名 USER SUSER_NAME 用户数据库ID数字 UID USER_ID 用户数据库名 USER USER_NAME 当前用户 CURRENT_USER CURRENT_USER 用户环境(audit trail) USERENV N/A 在CONNECT BY子句中的级别 LEVEL N/A ...
一、基础语法-- 开窗函数基本语法SELECTcolumn1,column2,window_function()OVER([PARTITIONBYpartition_...
We recommend that you not use time-dependent functions, such as RAND(), within a NULLIF function. This could cause the function to be evaluated twice and to return different results from the two invocations. Examples A. Returning budget amounts that have not changed ...
NULLIF is equivalent to a searched CASE expression in which the two expressions are equal and the resulting expression is NULL.We recommend that you not use time-dependent functions, such as RAND(), within a NULLIF function. This could cause the function to be evaluated twice and to return ...
nullif function nullifzero function nvl function nvl2 function octet_length function or operator overlay function parse_json function parse_url function percent_rank function percentile function percentile_approx function percentile_cont function percentile_disc function percentsign operator pi function pipepipe...
SQL函数 NULLIF SQL函数 NULLIF 如果两个表达式具有相同的值,则返回NULL的函数。 大纲 代码语言:javascript 复制 NULLIF(expression1,expression2) 参数 expression1- 表达式,可以是列名、数字或字符串文字、主变量或另一个标量函数的结果。 expression2- 表达式,可以是列名、数字或字符串文字、主变量或另一个标量函数...