如何在存储过程查询中使用IF条件

Question

Here is my Stored procedure Query. Here if typee is existing it should add the 2nd condition or it should not add. My table structure is like this

|id | name | typee |is_primary|
|1  |IND   |0      |1         |
|2  |SRIL  |1      |0         |

My Stored Procedure query is following

CREATE DEFINER=`root`@`localhost` PROCEDURE `testIfCondition`(IN countryId int(11),IN typee INT(11),IN is_primary INT(11),
out name VARCHAR(50))
BEGIN
     select name from country where id = id
        if typee != 0 then
          and typee= typee 
        end if;
       if is_primary !=0 then
          and primary = primary 
        end if;
END

In the above query which ever is having values has to get execute. If anyone know please help me out in this. When i am trying it is giving some syntax error. Please tell me correct syntax to solve my issue.

Thanks in advance !!!!

Answer 1

I don't think that you could add more condition using the IF statement. You can probably select it twice or more and add it to a temporary table , for example like this:

First create the temporary table

DECLARE @tempTable TABLE (
    ID INT,
    Name NVARCHAR(250),
    Typee INT
)

Then insert the first SELECT result to the @tempTable

INSERT INTO @tempTable
SELECT * FROM country WHERE id = countryId

Then use the condition to check if the typee is NULL or not

IF typee IS NOT NULL AND is_primary IS NOT NULL THEN
    SELECT * FROM @tempTable WHERE typee = typee AND is_primary = is_primary
ELSE IF typee IS NOT NULL THEN
    SELECT * FROM @tempTable WHERE typee = typee
ELSE IF is_primary IS NOT NULL THEN
    SELECT * FROM @tempTable WHERE is_primary = is_primary
ELSE
    SELECT * FROM @tempTable
END

though I think this is not the best practice to do it.

EDIT:

Based on the other answer here , you could create the query into a string first, then execute it. Your sp should look like this:

CREATE DEFINER=`root`@`localhost` PROCEDURE `testIfCondition`(IN countryId int(11),IN typee INT(11),IN is_primary INT(11),
out name VARCHAR(50))
BEGIN
    SET @query = CONCAT('select name from country where id = ', countryId);
    if typee <> 0 then
        SET @query = CONCAT(@query, ' AND typee = ', typee);
    end if;
    if is_primary <> 0 then
        SET @query = CONCAT(@query, ' AND is_primary = ', is_primary);
    end if;

    PREPARE stmt FROM @query;
    EXECUTE stmt;
    DEALLOCATE PREPARE stmt;
END

You can look here to see the execute query from the string.