SQL seems to be the most neglected language when it comes to formatting nicely and readably... And as SQL statements can be incredibly detailed and complex, it makes it extremely hard to work with. But I find that when I try to format my SQL code in the best way possible I'm sometimes unsure of how to do it. I know the standards for Java, C#, Python, etc.... but when it comes to SQL I haven't seen too many guidelines or accepted practices. What are tips/rules for formatting SQL so that it's clear, legible, and logical? Can you give example code to illustrate? What have you found to be the most standard, accepted way of formatting SQL?
You could try checking out Joe Celko's book SQL Programming Style. I'm sure that there are a lot of people who disagree with his style, but it's a good start.
Some of my own "rules"
For example:
SELECT
column_1,
column_2,
CASE
WHEN column_5 = 'Blah' THEN 1
WHEN column_6 = 'Blah' THEN 2
ELSE 3
END AS column_alias
FROM
My_Table MT
INNER JOIN My_Other_Table MOT ON
MOT.column_1 = MT.column_1
WHERE
MT.column_2 = 'Some Value' AND
(
MT.column_3 = 'Some other value' OR
MT.column_4 = 'Some other value'
)
Maybe this s "cheating" ;) - but I just found an amazing site that does this for you!
http://poorsql.com
And the options are fully customizable
I generally follow this type of syntax for MSSQL Server
SELECT statemenets
SELECT //optionally specify top or distinct
Field1,
Field2,
CASE WHEN (1 = 1) THEN
"1"
ELSE
"2"
END AS Field3,
...
FROM Table1 t1
INNER JOIN Table2 t2
ON t2.field1 = t1.field1 //I always reference the joined tables field name first
LEFT OUTER JOIN Table3 t3
ON (t3.field1 = t1.field1
AND t3.field2 = t2.field2) //I specify and with a new line and tabbed in
OR // I specify or(s) on thier own line this way you can distinguish from the two conditionals that need to be met
(t3.field1 = t2.field1
AND t3.field2 = t1.field2)
WHERE
(t1.Field1 = 'foo'
AND t1.field2 = 'bar')
OR
(t2.Field1 = 'foo'
AND t1.field2 = 'bar')
Derived Tables in a Select
Select
Field1,
Field2,
...
FROM (Select
Field1,
Field2,
Field3)
FROM Table1
WHERE
Field1 = '1') t1
Update Statements
UPDATE Table1
SET
Field1 = 1,
Field2 = 2,
Field3 = 3
WHERE
(Field1 = 2
AND Field3 = 2)
OR
(Field3 = 1)
Insert Statements
INSERT INTO Table1
(Field1,
Field2,
Field3,
...)
VALUES
(1,
2,
3,
...)
If Statements
IF (some condition) BEGIN
END ELSE BEGIN
END
Procedures
CREATE PROCEDURE Foo (
Bar INT,
Foo VARCHAR(20)
) AS
BEGIN
//Your Code Here
END
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With