强制存储过程在将数据插入表中之前进行检查

Question

I created this Stored Procedure,

Now what I want to do is, to always replace if a similiar type of record exists within table,

here's the sp,

USE [DBName]
GO

CREATE procedure [dbo].[InsertDD]
(
    @ColumnA varchar(1000), 
    @ColumnB varchar(1000),
    @CurrentDateAndTime datetime

)
AS

INSERT Into TableName
(
    ColumnA,    
    ColumnB,
    CurrentDateAndTime
)
Values
(
    @ColumnA,   
    @ColumnB,
    @CurrentDateAndTime
)

Now If table already has Column B value (regardless of difference in letters eg capital or lower case) then just update CurrentDateAndTime value.

If not then simply add three of the values.

Answer 1

Do the update, and if it didn't find any record to update, do the insert:

update TableName 
set CurrentDateAndTime = @CurrentDateAndTime
where ColumnB = @ColumnB

if (@@rowcount = 0) begin

  insert into TableName (
    ColumnA,    
    ColumnB,
    CurrentDateAndTime
  ) values (
    @ColumnA,   
    @ColumnB,
    @CurrentDateAndTime
  )

end

Answer 2

Have a search for the IF ... EXISTS command. Ultimatily you can also use the MERGE statement, which determines using a SELECT if a row already exists and you can do a UPDATE.