Multiple conditions without using multiple if else in SQL - sql

Question

I have to write a program in SQL that has multiple conditions but I shouldn't write it with multiple if else (because of the cost that if has). I'm new in this field and I have no idea how else could I write it which would be better
here is my sample code:
IF EXISTS(SELECT * FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA= 'dbo' AND TABLE_NAME = 'Food_tbl')
BEGIN
IF NOT EXISTS (SELECT TOP 1 FID FROM dbo.Food_tbl)
BEGIN
INSERT INTO dbo.Food_tbl
SELECT *
FROM DataFoodView
END
ELSE IF (SELECT COUNT(*) FROM dbo.Food_tbl)=20
BEGIN
PRINT N'Table Exists'
SELECT *
FROM Food_tbl
END
ELSE IF (SELECT COUNT(*) FROM dbo.FoodSara_tbl)<>20
BEGIN
print N'there isnt 20'
INSERT INTO Food_tbl (Food_tbl.FID, Food_tbl.Fname, Food_tbl.Ftype, Food_tbl.Fcount, Food_tbl.Datetype, Food_tbl.Fdescription)
SELECT DataFoodView.*
FROM DataFoodView
LEFT JOIN FoodSara_tbl ON Food_tbl.FID = DataFoodView.FID
WHERE Food_tbl.FID IS NULL;
END
END
PS: I have at first check if the table is exits and if it hasn't any record insert all the data, if it has 20 records show the table, if the table doesn't have 20 records find the missing data then insert that.

Answer 1

First, the condition in the ELSE part isn't needed :
change
ELSE IF (SELECT COUNT(*) FROM dbo.FoodSara_tbl)<>20
BEGIN
to
ELSE
BEGIN
Next, you may regroup the two INSERT parts because having no element is also having else than 20 elements.
The result will be something like that :
IF EXISTS
(
SELECT * FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA= 'dbo' AND TABLE_NAME = 'Food_tbl'
)
BEGIN
IF (SELECT COUNT(*) FROM dbo.Food_tbl)=20
BEGIN
PRINT N'Table Exists'
SELECT *
FROM Food_tbl
END
ELSE
BEGIN
print N'there isnt 20'
INSERT INTO Food_tbl (Food_tbl.FID, Food_tbl.Fname, Food_tbl.Ftype,
Food_tbl.Fcount, Food_tbl.Datetype, Food_tbl.Fdescription)
SELECT DataFoodView.*
FROM DataFoodView
LEFT JOIN FoodSara_tbl ON Food_tbl.FID = DataFoodView.FID
WHERE Food_tbl.FID IS NULL;
END
END

Answer 2

Not understood the exact requirement from the description what you have provided but just review the following logic
IF EXISTS(SELECT * FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA= 'dbo' AND TABLE_NAME = 'Food_tbl')
BEGIN
DECLARE #RCount INT
SELECT #RCount= COUNT(FID) FROM dbo.Food_tbl
IF #RCount=0
BEGIN
//Your Logic 1 (for inserting data since no records found)
END
ELSE
BEGIN
PRINT N'Table Exists'
IF #RCount=20
BEGIN
//Your Logic 2
END
ELSE
BEGIN
//Your Logic 3
END
END
END
Please explain the requirement in details or build your queries based on the requirement and add in place of Logic 1,2,3