mysql case / when语句在过程中

Question

我在第一个“;”之后仍然收到1064语法错误。 在第一个when语句中。 我试图从这里到这里都无济于事。 帮助任何人？

DELIMITER //

CREATE PROCEDURE `test` ()
BEGIN
    SELECT *,
        case 
        when variable_1 between 0.75 and 4     then 4;
        when variable_1 between 0    and 0.74  then "<4";
        when variable_1 between 4.1  and 365  then ">4";
        end case as variable_2;
END //

回答之后的修正问题：

实际代码：

DELIMITER //

CREATE PROCEDURE `infant_outcomes`.`new_procedure` ()
BEGIN
SELECT * FROM CDI

        INNER JOIN


    -- CDI subquery grouping and filtering 
    (SELECT CDI.subj_CDI as subj_CDI_grouping, Min(hearing_age_CDI) min_hearing_age_CDI,
    case 
    when CDI.hearing_age_CDI between 1.75 and 4.25 then 3
    when CDI.hearing_age_CDI between 4.75 and 7.25 then 6

    end as hearing_age_CDI_group
    FROM CDI
    group by CDI.subj_CDI, hearing_age_CDI_group
    ORDER BY CDI.subj_CDI, CDI.hearing_age_CDI ASC) CDI_filtered

        on
            CDI.subj_CDI = subj_CDI_grouping
            AND CDI.hearing_age_CDI = CDI_filtered.min_hearing_age_CDI

    where hearing_age_CDI_group is not null
    ORDER BY 
    CDI.subj_CDI, CDI_filtered.hearing_age_CDI_group
END //

我在“结尾//”处遇到语法错误，虽然以下两个答案组合起作用，但实际代码本身会引发该错误...

Answer 1

因为你断了语句。

SELECT *,
    case 
    when variable_1 between 0.75 and 4     then "4"
    when variable_1 between 0    and 0.74  then "<4"
    when variable_1 between 4.1  and 365  then ">4"
    end as variable_2;

您错过了分号

ORDER BY 
CDI.subj_CDI, CDI_filtered.hearing_age_CDI_group;
                                                ^________ this.

Answer 2

大小写表达式以“ end”结尾，而不是“ end case”。

删除尾随的“ case”：

DELIMITER //

CREATE PROCEDURE `test` ()
BEGIN
    SELECT *,
        case 
        when variable_1 between 0.75 and 4     then 4;
        when variable_1 between 0    and 0.74  then "<4";
        when variable_1 between 4.1  and 365  then ">4";
        end as variable_2; -- "case" removed
END //