Question

I have a situation where I’m parsing a varchar value to extract numbers, and I have to update my table to put the numeric value into a new field in my table. I have encapsulated the string parsing into a stored proc. Now I’m trying to write the update statement.

MY table looks like this (simplified to show only the key values):

CREATE TABLE dbo.oper_pacer
(
oper_pacer_id                 int         NOT NULL,
oper_pacer_fluroscopy         varchar(20) NULL,
oper_pacer_fluoro_min         float       NULL
)

My function takes a varchar(20) value and returns a float, doing the parsing and conversion of the number:

CREATE FUNCTION usf_ParseFluoro( 
@parm1 VARCHAR(20)
)
RETURNS FLOAT
AS
BEGIN
    DECLARE @value VARCHAR(20)
    DECLARE @midVal VARCHAR(20)
    DECLARE @nPos INT
    DECLARE @lPos INT

SELECT @midVal = SUBSTRING(@parm1, PATINDEX('%[0-9]%', @parm1), PATINDEX('%[0-9]%',@parm1) + LEN(@parm1)+1)

SELECT @value = 
    (CASE 
        WHEN PATINDEX('%[a-z]%', @midVal) = 0
            THEN @midVal
        ELSE RTRIM(SUBSTRING(@midVal, 1, PATINDEX('%[a-z]%', @midVal)-1))
    END)

    RETURN CONVERT(FLOAT, @value)
END

Here’s my problem:

How do I write the update of my original table, to loop through, calling the function, and putting the return value into oper_pacer_fluoro_min, given that there’s no way to do a for each loop in T-SQL?

EDIT:
Once I created the function, the Update was pretty simple, with a little trial and error: I needed to put in the dbo. prefix to the function to get it to run with my current DB permissions:

UPDATE oper_pacer SET oper_pacer_fluoro_min = dbo.usf_ParseFluoro(oper_pacer_fluroscopy)

Answer 1

I don’t think you can do it using a procedure. I solved a similar problem using a function, and I think it would work for you as well. You may need to restructure your table (even if it’s in a temporary table), so that you’ll have all of the necessary data elements available to the function. But once you do that, your UPDATE statment is just the function call on the input field.