CASE表达式是用来判断条件的,条件成立时返回某个值,条件不成立时返回另一个值。 语法: CASEWHENComparsionConditionTHENresultWHENComparsionConditionTHENresultELSEotherEND (注:各分支返回的数据类型需一致。) (注:when子句一定要有排他性,因为当when子句为真时,剩余的when子句会被忽略。) CASE表达式的用途: 1,转换...
SQL 条件语句 (IF, CASE WHEN, IFNULL) 1、IF 1.1 表达式: IF( expr1 , expr2 , expr3 ) expr1条件,条件为true,则值是expr2 ,false,值就是expr3 示例; SELECT o.id,u.account,catagory
Why is the CASE Statement Important? The CASE WHEN statement is a valuable tool in SQL queries, offering several key benefits: Data transformation: enables you to create new columns based on the values of existing columns. Conditional aggregation: allows you to create aggregated values (e.g., ...
CASE WHEN 和COUNT CASE WHEN 和SUM CASE WHEN 和 AVG函数 与AVG函数结合,可实现计算百分比的功能 部分例子参考来自:https://www.sqlshack.com/case-statement-in-sql 你的点赞是我持续更新的动力~ 谢谢 Thanks♪(・ω・)ノ SQL学习笔记 友情链接: Y:SQL学习笔记 - 窗口函数OVER19 赞同 · 0 评论...
CASE 陳述式有兩種類型: 簡式case 陳述式: 用來根據文字值輸入部分邏輯 搜尋的 case 陳述式: 用來根據表示式的值輸入部分邏輯 CASE 陳述式的 WHEN 子句定義當滿足時決定控制流程的值。 以下是具有含簡式 case-statement-when-clause 之 CASE 陳述式的 SQL 程序範例: CREATE PROCEDURE UPDATE_DEPT (IN p_workde...
SELECTcolumn1, column2, ...CASEWHENcondition1THENresult1WHENcondition2THENresult2-- Add more WHEN conditions and results as neededENDASalias_nameFROMtable_name; We can add as manyWHEN ... THENconditions as required in theCASEstatement. For example, ...
CASE WHEN `距离` < 100 THEN 100 WHEN `距离` < 500 THEN 500 ELSE 1000 END WHERE `距离` < 1000; (3)IF...ELSE语句 IF search_condition THEN statement_list [ELSEIF search_condition THEN] statement_list ... [ELSE statement_list]
–简单Case函数 CASE sex WHEN ‘1’ THEN ‘男’ WHEN ‘2’ THEN ‘女’ ELSE ‘其他’ END ...
SELECTTOP10qs.last_execution_time, st.textASbatch_text,SUBSTRING(st.TEXT, (qs.statement_start_offset /2) +1, ((CASEqs.statement_end_offsetWHEN-1THENDATALENGTH(st.TEXT)ELSEqs.statement_end_offsetEND- qs.statement_start_offset) /2) +1)ASstatement_text, (qs.total_worker_time /1000) / ...
NOTE: SQL commands are not case sensitive. The above SELECT statement can also be written as"select first_name from students_details;" You can also retrieve data from more than one column. For example, to select first name and last name of all the students. ...