Search results
Results from the WOW.Com Content Network
It is the same both 'on' or 'where' on an inner join as long as your server can get it: select * from a inner join b on a.c = b.c. and. select * from a inner join b where a.c = b.c. The 'where' option not all interpreters know so maybe should be avoided. And of course the 'on' clause is clearer.
2. This answer contains some wrong and muddled writing. 1. For INNER JOIN any condition can be in a WHERE instead of an ON as long as there is no intervening OUTER JOIN. 2. When moving a LEFT JOIN condition from an ON to a WHERE the performance is irrelevant since (as you say) in general the result differs. 3.
1. Equi JOIN : For whatever JOIN type (INNER, OUTER, etc), if we use ONLY the equality operator (=), then we say that the JOIN is an EQUI JOIN. 2. Theta JOIN : This is same as EQUI JOIN but it allows all other operators like >, <, >= etc. Many consider both EQUI JOIN and Theta JOIN similar to INNER, OUTER etc JOIN s.
SELECT ks, COUNT(*) AS '# Late' FROM Table WHERE Age > Palt GROUP BY ks. which returns: ks # Late. person1 1. person2 1. And I want to join the results of these two select statements (by the KS) I'm trying to avoid using a temp table, but if that's the only practical way to do this, I'd like to know more about using temp tables in this fashion.
INNER JOIN = JOIN. INNER JOIN is the default if you don't specify the type when you use the word JOIN. You can also use LEFT OUTER JOIN or RIGHT OUTER JOIN, in which case the word OUTER is optional, or you can specify CROSS JOIN. OR. For an INNER JOIN, the syntax is:
LEFT JOIN Y AS ybar ON (ybar.value = 'bar' AND some other complex stuff) JOIN Y ON Y.id IN (yfoo.id, ybar.id) -- 'magic' happens here. Instead of one join with OR it turned into three joins. With each condition in a seprate join and a final join to get that one matching row from either first or second join.
I believe 'AS' used to be a required keyword, but is no longer needed, only for readability. I find 'As' is often used when creating a name for a data item in the SELECT, but not when giving a name to a table in a JOIN. For example: SELECT t.ID as TestID FROM [House] h JOIN [TestCase] t ON t.ID=h.TestID. I think this is probably because a set ...
1. To perform an UPDATE statement with a JOIN in SQL Server, you can use the JOIN syntax in combination with the UPDATE statement. Here's an example query that should update the ud table based on the corresponding values from the sale table: UPDATE ud. SET ud.assid = sale.assid.
Since all records match, the result is the same as the INNER JOIN. However, adding a record to table1 for which there is no match in table2. INSERT INTO table1 (WeddingTable, TableSeat, TableSeatID, Name) VALUES (003, 002, 003002, 'Arielle'); the LEFT OUTER JOIN query will now produce a different result than the INNER JOIN.
A CASE expression returns a value from the THEN portion of the clause. You could use it thusly: SELECT * FROM sys.indexes i JOIN sys.partitions p ON i.index_id = p.index_id JOIN sys.allocation_units a ON CASE WHEN a.type IN (1, 3) AND a.container_id = p.hobt_id THEN 1 WHEN a.type IN (2) AND a.container_id = p.partition_id THEN 1 ELSE 0 END = 1