So the problem is the JOIN to the query_header table. SELECT @rownum := @rownum + 1 AS rank, qc.field_name,qc.query_header,qc.sort_order FROM query_columns qc JOIN ( SELECT @rownum := 0 ) r WHERE qc.query_header = 1 ORDER BY qc.sort_order; Output: +---+---+-...
User variables, even though not part of standard SQL, are great objects in MySQL. They allow to keep some “state” for the life of a session: a session can execute a statement to compute a value, store that value in a user variable, and use it in all next statements. This avoids ...
DELIMITER $$ DROP PROCEDURE IF EXISTS siteindex.getRandomTags$$ CREATE PROCEDURE siteindex.getRandomTags() BEGIN DECLARE rnd_1 INT DEFAULT 0; DECLARE rnd_2 INT DEFAULT 0; DECLARE rnd_3 INT DEFAULT 0; DECLARE rownum INT DEFAULT 0; SELECT COUNT(*) INTO rownum FROM tagstab; set rownum =...
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If you do want to make a comparison, consider it as learning linear algebra: by putting all that effort into this one subject, you know that you will be able to use it to master machine learning as well. In short, this is why you should learn this query language: ...
'WHEN MATCHED' cannot appear more than once in a 'UPDATE' clause of a MERGE statement. "EXECUTE AT" with Dynamic Linked Server Name "explicit value must be specified for identity column in table" error in SQL 2000 "FROM clause have the same exposed ...
You’ll also see that these anti-patterns stem from performance concerns and that, besides the “manual” approach to improving SQL queries, you can analyze your queries also in a more structured, in-depth way by making use of some other tools that help you to see the query plan; And, ...
"explicit value must be specified for identity column in table" error in SQL 2000 "FROM clause have the same exposed names. Use correlation names to distinguish them" "No transaction is active." error when trying to send a transactional SQL statment over MSDTC "Restricted data type attribute...
Use the SQL command DROP VIEW to drop a view. For example: DROP VIEW Accounts_staff; Modifying a Join View Oracle allows you, with some restrictions, to modify views that involve joins. Consider the following simple view: CREATE VIEW Emp_view AS ...
(I have found a alternative for rownum, but with the constraint rownum <= 100 it doesn´t work.) 5) SELECT tab1, tab2, SUM(tab2) OVER (PARTITION BY tab1) as res1, tab3, SUM(tab3) OVER (PARTITION BY tab1) as res2,