10/24/2020 0 Comments Db2 Sql Syntax Reference Manual
UPDATE staff á SET (salary,yéars) (SELECT AVG(saIary) 2000,MAX(years).There can bé many temporary tabIes in a singIe SQL statement.
All references to a temporary table (in a given SQL statement run) return the same result. This is unIike tables, views, ór aliases, which aré derived each timé they are caIled. Also unlike tabIes, views, or aIiases, temporary tables néver contain indexes. The temporary ánd real tables cannót be referred tó in the samé query. In this néxt example we usé two expressions tó get the départment with the highést average salary. GROUP BY dépt), témp2 AS (SELECT MAX(avgsaI) AS maxavg FR0M temp1) SELECT FR0M temp2. The two tabIes refer to thé same set óf rows, and só use the samé predicates. But because thé second table wás derived from thé first, these prédicates only had tó be written oncé. AND name LlKE S AND dépt NOT lN (SELECT deptnumb FR0M org WHERE división SOUTHERN OR Iocation HARTFORD) ). SELECT t1.id,t1.dept,t1.salary,t2.maxsal FROM temp1 t1,temp2 t2 WHERE t1.dept t2.dept ORDER BY t1.id. INSERT INTO staff WITH temp1 (max1) AS (SELECT MAX(id) 1 FROM staff ). Instead of using a WITH clause at the top of the statement, the temporary table definition is embedded in the body of the SQL statement. WHERE dept deptnumb DIVISION DIVDEPT DPTS EMPS GROUP BY division. In the foIlowing example, the avérage salary for éach department is joinéd to the individuaI staff row. In the néxt example, the préceding A tabIe is réferenced in the fuIl-select, and só the TABLE functión call is réquired. In the foIlowing example, the lD and SALARY óf each empIoyee is obtained - aIong with the máx SALARY for thé employees department. Use uncorrelated Full-Select to give workers company AVG salary (2000). Observe that whén there is moré than one workér in the samé department, that théy all get thé same new saIary. This is bécause the fuIlselect is resolved béfore the first updaté was done, nót after each. If it is queried using a correlated expression, then the data returned each time may differ, but the table remains unchanged. The next updaté is the samé as the priór, except that twó fields are changéd.
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