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Writing more legible SQL

craigkerstiens.com

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Re: Writing more legible SQL

#11

Post by rubyfan »

combatentropy wrote: post #10

Here is how I write SQL: select t1.col1, t2.col2, t3.col3 from table1 t1 join table2 t2 on t1.col2 = t2.col1 join table3 t3 on t1.col3 = t3.col1 and t3.col2 = something_else where t1.col1 > 0 and t2.col2 t1.col4 order by col2 limit 100 So: 1. SQL capitalization is not sacred. I lowercase everything. 2. I just indent subclauses, with four spaces, like I indent other languages. I don't go out of my way to line up thing…

I go back and forth with conjunction at the end or beginning of the line. At the end you get to line up column names, at the beginning it makes it easier to comment out or remove the line and basically contains the intended logic on a single line.

I think I usually end up with the later because I think it makes more sense.

Re: Writing more legible SQL

#12

Post by emmelaich »

combatentropy wrote: post #10

Here is how I write SQL: select t1.col1, t2.col2, t3.col3 from table1 t1 join table2 t2 on t1.col2 = t2.col1 join table3 t3 on t1.col3 = t3.col1 and t3.col2 = something_else where t1.col1 > 0 and t2.col2 t1.col4 order by col2 limit 100 So: 1. SQL capitalization is not sacred. I lowercase everything. 2. I just indent subclauses, with four spaces, like I indent other languages. I don't go out of my way to line up thing…

Oh yes please. Capitals just make it harder to read.

Re: Writing more legible SQL

#13

Post by walrus »

combatentropy wrote: post #10

Here is how I write SQL: select t1.col1, t2.col2, t3.col3 from table1 t1 join table2 t2 on t1.col2 = t2.col1 join table3 t3 on t1.col3 = t3.col1 and t3.col2 = something_else where t1.col1 > 0 and t2.col2 t1.col4 order by col2 limit 100 So: 1. SQL capitalization is not sacred. I lowercase everything. 2. I just indent subclauses, with four spaces, like I indent other languages. I don't go out of my way to line up thing…

Interesting! I independently ended up on nearly the exact same style. The only difference is I don't indent join clauses.

Re: Writing more legible SQL

#15

Post by NDizzle »

jjp wrote: post #7

Would have been useful to see some thinking on joins and the naming conventions when you have the same column in both tables

Use aliases, and if you have more than two joins you should prefix every column, unless the column names are obvious.

Re: Writing more legible SQL

#16

Post by jm547ster »

combatentropy wrote: post #10

Here is how I write SQL: select t1.col1, t2.col2, t3.col3 from table1 t1 join table2 t2 on t1.col2 = t2.col1 join table3 t3 on t1.col3 = t3.col1 and t3.col2 = something_else where t1.col1 > 0 and t2.col2 t1.col4 order by col2 limit 100 So: 1. SQL capitalization is not sacred. I lowercase everything. 2. I just indent subclauses, with four spaces, like I indent other languages. I don't go out of my way to line up thing…

"2. I just indent subclauses, with four spaces,"

Surely you mean tabs? runs

Re: Writing more legible SQL

#17

Post by Revell »

I write my SQL as follows:

    SELECT `second_column`,
           `fourth_column`
      FROM `table_name`
     WHERE `first_column` = 'Value'
       AND `third_column` = 3
  ORDER BY `fifth_column` ASC
     LIMIT 1

Re: Writing more legible SQL

#19

Post by julochrobak »

combatentropy wrote: post #10

Here is how I write SQL: select t1.col1, t2.col2, t3.col3 from table1 t1 join table2 t2 on t1.col2 = t2.col1 join table3 t3 on t1.col3 = t3.col1 and t3.col2 = something_else where t1.col1 > 0 and t2.col2 t1.col4 order by col2 limit 100 So: 1. SQL capitalization is not sacred. I lowercase everything. 2. I just indent subclauses, with four spaces, like I indent other languages. I don't go out of my way to line up thing…

quick question about the indent of subclauses. How would you write a query where table3 needs to be joined with both table1 and table2? Would it change anything?
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