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53. SQL. SELECT:
SELECT (., ) DML SQL, () , .
, . JOIN. , (. view) (. stored procedure), .
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SELECT :
SELECT [DISTINCT | DISTINCTROW | ALL] select_expression,... FROM table_references [WHERE where_definition] [GROUP BY {unsigned_integer | col_name | formula}] [HAVING where_definition] [ORDER BY {unsigned_integer | col_name | formula} [ASC | DESC],...]:
SELECT FROM WHERE
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, SELECT:
WHERE , GROUP BY.
GROUP BY .
HAVING , GROUP BY .
ORDER BY , .
T | ||||||||||||||
| SELECT * FROM T; |
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| SELECT C1 FROM T; |
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| SELECT * FROM T WHERE C1 = 1; |
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| SELECT * FROM T ORDER BY C1 DESC; |
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T
SELECT * FROM T;.
SELECT C1 FROM T;C1 , .
SELECT * FROM T WHERE C1 = 1;, C1 '1' , , WHERE.
SELECT * FROM T ORDER BY C1 DESC;, , (Z-A) - ORDER BY C1 . WHERE, , . ORDER BY [. ORDER BY C1 ASC, C2 DESC] .
column_name value1,value2,
SELECT * FROM table_nameWHERE column_name IN (value1,value2,...)