How replace with exists?
An alternative for IN and EXISTS is an INNER JOIN, while a LEFT OUTER JOIN with a WHERE clause checking for NULL values can be used as an alternative for NOT IN and NOT EXISTS.
How do you replace not exists with join in SQL?
select distinct a.id, a.name from Employee a join Dependencies b on a.id = b. eid where not exists ( select * from Dependencies d where b.id = d.id and d.name = ‘Apple’ ) and exists ( select * from Dependencies c where b.id = c.id and c.name = ‘Orange’ );
How do you replace an item in SQL?
To replace all occurrences of a substring within a string with a new substring, you use the REPLACE() function as follows:
- REPLACE(input_string, substring, new_substring); …
- SELECT REPLACE( ‘It is a good tea at the famous tea store.’, ‘
How do you use exists?
The EXISTS condition in SQL is used to check whether the result of a correlated nested query is empty (contains no tuples) or not. The result of EXISTS is a boolean value True or False. It can be used in a SELECT, UPDATE, INSERT or DELETE statement.
Which is better in or exists SQL?
The EXISTS clause is much faster than IN when the subquery results is very large. Conversely, the IN clause is faster than EXISTS when the subquery results is very small. Also, the IN clause can’t compare anything with NULL values, but the EXISTS clause can compare everything with NULLs.
What is the difference between not in and not exists?
not in can also take literal values whereas not exists need a query to compare the results with. EDIT: not exists could be good to use because it can join with the outer query & can lead to usage of index, if the criteria uses column that is indexed.
Which is faster join or exists?
In most cases, EXISTS or JOIN will be much more efficient (and faster) than an IN statement. … With an EXISTS or a JOIN, the database will return true/false while checking the relationship specified. Unless the table in the subquery is very small, EXISTS or JOIN will perform much better than IN.
Which is faster Left join or not exists?
Many years ago (SQL Server 6.0 ish), LEFT JOIN was quicker, but that hasn’t been the case for a very long time. These days, NOT EXISTS is marginally faster. The biggest impact in Access is that the JOIN method has to complete the join before filtering it, constructing the joined set in memory.
Is NULL vs not exists?
The NULL is considered and returned by the NOT IN command as a value. The SQL NOT EXISTS command is used to check for the existence of specific values in the provided subquery. The subquery will not return any data; it returns TRUE or FALSE values depend on the subquery values existence check.
Why replace is used in SQL?
Replace in SQL is a built-in function that allows you to replace all the incidents of a substring within a specified string with a new substring. Thus, whenever you want to replace something like a dead link or a product name, the replace() function is the way to go.
How do I remove a space in SQL?
SQL Server TRIM() Function
The TRIM() function removes the space character OR other specified characters from the start or end of a string. By default, the TRIM() function removes leading and trailing spaces from a string. Note: Also look at the LTRIM() and RTRIM() functions.
What is replace in SQL?
The REPLACE() function replaces all occurrences of a substring within a string, with a new substring. Note: The search is case-insensitive.