使用IN关键字在SQL查询中无法将参数值从字符串转换为Int64

Question

I have following table structures.

  **Table_A**
        A_Id(BigInt)    Category_Ids(varchar(50))
        1                        1,2,3
        2                         2,3

    **Table_B**
        B_Id(BigInt)    C_Id(Bigint)    Name(varchar(50))
        1                         2              A
        2                         1              C
        3                         3              B

First Query: In this query want to get the record where A_Id=1. I have executed following code. Select [Category_Ids] from Table_A where A_Id=1 This returns the data table with single column and single row with values “1, 2, 3” Assume that above query fills the data into the A_datatable. I get the string from following code. String ids = A_datatable.column[0][“Category_Ids”];

Second Query: Now, I have to fetch the values from Table_B where C_Id in (1, 2, 3). I have executed following code and passed the string value to following query. Select * from Table_B where C_Id in (ids) When I execute above query getting the error, failed to convert parameter value from a String to a Int64.

Answer 1

You can actually do it in a single query.

SELECT  b.*
FROM    Table_A a
        INNER JOIN Table_B b
            ON ',' + a.Category_IDs + ',' LIKE '%,' + CAST(C_ID AS VARCHAR(10)) + ',%'
WHERE   a.A_ID = 1

Caveat: This query is an index-killer. You should have properly normalize your tables.

UPDATE 1

Suggested Schema Design,

Table_A

• A_ID
• Category_ID

Table_C

• B_ID
• C_ID
• Name

---

Records

Table_A

A_ID    Category_ID
1       1
1       2
1       3
2       4
2       5

Table_B

B_Id    C_Id    Name
1       2       A
2       1       C
3       3       B

Answer 2

You can use a string splitter function like the one described here http://www.sqlservercentral.com/articles/Tally+Table/72993/

scroll down to the 'CREATE FUNCTION' script and run it to create your function, then you can split the comma separate string for use in your 'where in' clause

select * from Table_B
where C_Id in (select item from dbo.DelimitedSplit8K(IDS,','))