EXISTS(select 1 from t1) vs EXISTS(select * from t1)
63056
Subquery using Exists 1 or Exists *
113666
OR Operator Short-circuit in SQL Server
108832
Is a join optimized to a where clause at runtime?
4094
What is the difference between "INNER JOIN" and "OUTER JOIN"?
115431
What is the order of execution for this SQL statement
158902
What's the difference between where clause and on clause when table left join?
4521
Is there an "exists" function for jQuery?
113861
Exist vs exists in mathematics
1027
Why is this true? $(\exists x)(P(x) \Rightarrow (\forall y) P(y))$
75971
Is there a PL/SQL pragma similar to DETERMINISTIC, but for the scope of one single SQL SELECT?
120636
What is the question mark's significance in MySQL at "WHERE column = ?"?
13261
Return row only if value doesn't exist
103234
Implementing "where not exists" with NHibernate QueryOver
99497
IF EXISTS taking longer than embedded select statement
18575
How to 'insert if not exists' in MySQL?
61752
What's the difference between isset() and array_key_exists()?
5511
Check if table exists