LEAD in SQL Server 2008 - sql

Question

I have done a stored procedure with contains LEAD, unfortunately the script must run on 2008, so anyone know how to achieve this in 2008?
INSERT INTO #ARTICLES(EAN, ID_ART, QTE, PV_NET_HT)
SELECT EAN, ID_ART, QTE_CDE, PA_NET
FROM (
SELECT TEXTE_LIG,
CASE WHEN TEXTE_LIG LIKE '%++%' THEN ID_ART ELSE LEAD(ID_ART) OVER (ORDER BY (SELECT NULL)) END AS ID_ART,
CASE WHEN TEXTE_LIG LIKE '%++%' THEN CHAR01 ELSE LEAD(CHAR01) OVER (ORDER BY (SELECT NULL)) END AS EAN,
LEAD(QTE_CDE, CASE WHEN TEXTE_LIG LIKE '%++%' THEN 1 ELSE 2 END) OVER (ORDER BY (SELECT NULL)) AS QTE_CDE,
LEAD(PX_BASE, CASE WHEN TEXTE_LIG LIKE '%++%' THEN 2 ELSE 3 END, NULL) OVER (ORDER BY (SELECT NULL)) AS PX_BASE,
LEAD(PX_NET, CASE WHEN TEXTE_LIG LIKE '%++%' THEN 2 ELSE 3 END, NULL) OVER (ORDER BY (SELECT NULL)) AS PA_NET
FROM AMAZON_ACHATS_LIG
WHERE ID_ACHATS_ENT = #IDENTITY
) AS LIGNE
WHERE TEXTE_LIG LIKE 'LIN%';

Answer 1

To replace LEAD in 2008, you need to do a self join to the same table, to the next row. To do this, the easiest way is to have a contiguous ID of some sort, and you can join to the record with ID + one. If no suitable contiguous ID exists, then select your data in a CTE, and add a row_number to it. Then use that row_number in the outer query for the self join.
Incidentally, be aware there is no such thing as "keeping the database order". If you don't have an order specified for a given query, then SQL will decide the output order, which may be the same order as entry, or may be something totally different, or may be mostly the same order except for a few records. It may return totally different orders for the same query on different occasions, depending on which query plan it decides to use this time. If you want data to keep the same order it was entered in, you need to have an auto-incrementing identity column to ensure that is possible, or someday you will not get what you expect.
In your query, your various leads have offsets of none (same as 1), 1, 2 and 3, so you will need to self join three times to cover all of those options. In your query, you then replace each of the LEAD with the data from the correct self-joined table. You want something like this:
WITH BASEDATA AS (
--THIS IS YOUR BASIC DATA, WITH A ROW NUMBER ADDED
-- DO THIS AS A CTE, SO YOU CAN JOIN TO IT MULTIPLE TIMES
SELECT TEXTE_LIG, ID_ART, CHAR01, QTE_CDE, PX_BASE, PX_NET, ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS RowNo
FROM AMAZON_ACHATS_LIG
WHERE ID_ACHATS_ENT = #IDENTITY
)
INSERT INTO #ARTICLES(EAN, ID_ART, QTE, PV_NET_HT)
SELECT EAN, ID_ART, QTE_CDE, PA_NET
FROM (
SELECT TEXTE_LIG,
CASE WHEN TEXTE_LIG LIKE '%++%' THEN ID_ART ELSE B1.ID_ART END AS ID_ART,
CASE WHEN TEXTE_LIG LIKE '%++%' THEN CHAR01 ELSE B1.CHAR01 END AS EAN,
CASE WHEN TEXTE_LIG LIKE '%++%' THEN B1.QTE_CDE ELSE B2.QTE_CDE END AS QTE_CDE,
CASE WHEN TEXTE_LIG LIKE '%++%' THEN B2.PX_BASE ELSE B3.PX_BASE END AS PX_BASE,
CASE WHEN TEXTE_LIG LIKE '%++%' THEN B2.PX_NET ELSE B3.PX_NET END AS PA_NET
FROM BASEDATA B0 --THE BASIC DATA
LEFT OUTER JOIN BASEDATA B1 ON B1.RowNo = B0.RowNo + 1 --This is your LEAD (1) table
LEFT OUTER JOIN BASEDATA B2 ON B2.RowNo = B0.RowNo + 2 --This is your LEAD (2) table
LEFT OUTER JOIN BASEDATA B3 ON B3.RowNo = B0.RowNo + 3 --This is your LEAD (3) table
--WHERE ID_ACHATS_ENT = #IDENTITY --DON'T NEED THIS AMY MORE, DONE IN CTE
) AS LIGNE
WHERE TEXTE_LIG LIKE 'LIN%';