B. 使用 CONCAT 以及 NULL 值 SQL复制 CREATETABLE#temp ( emp_nameNVARCHAR(200)NOTNULL, emp_middlenameNVARCHAR(200)NULL, emp_lastnameNVARCHAR(200)NOTNULL);INSERTINTO#tempVALUES('Name',NULL,'Lastname');SELECTCONCAT(emp_name, emp_middlename, emp_lastname)ASResultFROM#temp; ...
BEGIN SCTX := WM_CONCAT_IMPL(NULL) ; RETURNODCICONST.SUCCESS; END; MEMBERFUNCTIONODCIAGGREGATEITERATE(SELFINOUTWM_CONCAT_IMPL, P1INVARCHAR2) RETURNNUMBER IS BEGIN IF(CURR_STRISNOTNULL)THEN CURR_STR := CURR_STR || ',' || P1; ELSE CURR_STR := P1; ENDIF; RETURNODCICONST.SUCCESS; END;...
SQL语句代码如下: 代码语言:javascript 复制 #-- fruit CREATE TABLE `user_like` ( `id` int(11) NOT NULL AUTO_INCREMENT, #--id `user_id` int, #--用户的id号 `fruit_id` int, #--水果的id号 CONSTRAINT user_like PRIMARY KEY (id,user_id,fruit_id) #--定义联合主键 让每一条记录唯一 ...
SELECT CONCAT('a', NULL, 'c'); 解决方法:使用 COALESCE 或IFNULL 函数处理空值。 代码语言:txt 复制 SELECT CONCAT('a', COALESCE(NULL, ''), 'c'); 参考链接 MySQL CONCAT 函数 如果你遇到具体的报错信息,请提供详细的错误信息,以便更准确地诊断问题并提供解决方案。 相关搜索: js concat方法报错 conc...
DROP TABLE IF EXISTS `lgs_operation_task_rules`; CREATE TABLE `lgs_operation_task_rules` ( `ID` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '主键', `site_id` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '站点id', ...
DECLARE @CONCAT_SETTING VARCHAR(3) = 'OFF'; IF ( (4096 & @@OPTIONS) = 4096 ) SET @CONCAT_SETTING = 'ON'; SELECT @CONCAT_SETTING AS CONCAT_NULL_YIELDS_NULL; Examples The following example showing using both SET CONCAT_NULL_YIELDS_NULL settings. sql Copy PRINT 'Setting CONCAT_NULL_...
SCTX// := WM_CONCAT_IMPL(NULL) ; RETURN ODCICONST.SUCCESS; END; MEMBER FUNCTION ODCIAGGREGATEITERATE(SELF IN OUT WM_CONCAT_IMPL,P1// IN VARCHAR2) RETURN NUMBER IS BEGIN IF(CURR_STR// IS NOT NULL) THEN CURR_STR// := CURR_STR// || ',' || P1//; ...
If CONCAT receives arguments with all NULL values, it returns an empty string of type varchar(1). The implicit conversion to strings follows the existing rules for data type conversions. For more information about data type conversions, see CAST and CONVERT (Transact-SQL)....
RETURNNUMBERISBEGINRETURNVALUE:=CURR_STR;RETURNODCICONST.SUCCESS;END;MEMBERFUNCTIONODCIAGGREGATEMERGE(SELFINOUTWM_CONCAT_IMPL_CLOB_NULL_LHR,SCTX2INWM_CONCAT_IMPL_CLOB_NULL_LHR)RETURNNUMBERISBEGINIF(SCTX2.CURR_STRISNOTNULL)THENSELF.CURR_STR:=SELF.CURR_STR||SCTX2.CURR_STR;ENDIF;RETURNODCICONST....
If, instead of using SUBSTR, you use TRIM and the first non-NULL value has the delimiter character as the first character(s) in the string then you will remove too many characters and the final row of the sample data would output NULL. Instead, it is better to remove only the number ...