I vaguely remember using a case clause in a select statement in a former occupation, but now that I am using mysql (with php) I am encountering my first need for it and don't know if I can do what I want. I need to add a sequencing field to my query results based upon whether ...
#在mysql_execute_command函数中,执行到case SQLCOM_SELECT,res= lex->m_sql_cmd->execute(thd),进入到execute函数 #在mysql_execute_command函数中,switch (lex->sql_command)通过case SQLCOM_XXX,转到不同语句的执行器 #这时候就进入到了lex的公共属性m_sql_cmd类下面的execute函数; #通过单步调试,此时程序...
SELECT @customerNo AS Customer, @country AS Country, @shipping AS Shipping; Here is the output: Searched CASE statement# The simple CASE statement only allows you match a value of an expression against a set of distinct values. In order to perform more complex matches such as ranges, you ...
Query:createfunctionNameByT()returnchar(50)return(select name from t3 where id=2)Error Code:1064You have an errorinyourSQLsyntax;check the manual that corresponds to your MySQL server versionforthe right syntax to use near 'returnchar(50)return(select name from t3 where id=2)' at line2Exe...
默认至少8位长|validate_password.mixed_case_count|1|## 密码至少包含1个大小写字母|validate_password.number_count|1|## 密码至少包含一个数字|validate_password.policy|MEDIUM|## 密码默认复杂度策略|validate_password.special_char_count|1|## 密码至少包含一个特殊字符+---+---+7rowsinset(0.0042sec)#...
SELECT CASE 1 WHEN 1 THEN 'this is case one' WHEN 2 THEN 'this is case two' ELSE 'this is not in the case' END as 'how to execute case statement'; Sample Output: mysql> SELECT CASE 1 WHEN 1 THEN 'this is case one' -> WHEN 2 THEN 'this is case two' ...
Cond1,cond2,…..,condN:表示在 CASE 语句列表中需要评估的条件。 Value1, value2, ...,valueN:表示满足条件时需要显示的各个值。 Value:表示 else 部分满足时显示的值。 这部分允许在 MySQL 的查询中添加逻辑 CASE 语句。为了生成有效的语句,我们在任何地方使用带有 WHERE SELECT 和 ...
CASE WHEN search_condition THEN statement_list [WHEN search_condition THEN statement_list] ... [ELSE statement_list] END CASE 注意: 这两种语法是有区别的,区别如下: 1:第一种语法:case_value必须是一个表达式,例如 userid%2=1或者username is null等。该种语法不能用于测试NULL。
13.2.9 SELECT Statement SELECT[ALL|DISTINCT|DISTINCTROW][HIGH_PRIORITY][STRAIGHT_JOIN][SQL_SMALL_RESULT][SQL_BIG_RESULT][SQL_BUFFER_RESULT][SQL_CACHE|SQL_NO_CACHE][SQL_CALC_FOUND_ROWS]select_expr[,select_expr]...[into_option][FROMtable_references[PARTITIONpartition_list]][WHEREwhere_condition...
htmlThe target table of theINSERTstatement may appear in theFROMclause of theSELECTpart of the ...