MySQL之SELECT-norilover的博客
mysql> HELP SELECT Name: 'SELECTDescription://描述
Syntax://语法
SELECT
select_expr [, select_expr ...]
[FROM table_references
[GROUP BY {col_name | expr | position}
, ... ]
[ORDER BY {col_name | expr | position}
, ...]
row_count | row_count OFFSET offset}]
[INTO OUTFILE 'file_name'
export_options
| INTO DUMPFILE 'file_name'
| INTO var_name [, var_name]]
]
SELECT is used to retrieve rows selected from one or more tables, and
can include UNION statements and subqueries. See , and
http://dev.mysql.com/doc/refman/5.5/en/subqueries.html.
The most commonly used clauses of SELECT statements are these:
o Each select_expr indicates a column that you want to retrieve. There
must be at least one select_expr.
o table_references indicates the table or tables from which to retrieve
rows. Its syntax is described in .
o The WHERE clause, if given, indicates the condition or conditions
that rows must satisfy to be selected. where_condition is an
expression that evaluates to true for each row to be selected. The
statement selects all rows if there is no WHERE clause.
In the WHERE expression, you can use any of the functions and
operators that MySQL supports, except for aggregate (summary)
functions. See
http://dev.mysql.com/doc/refman/5.5/en/expressions.html, and
http://dev.mysql.com/doc/refman/5.5/en/functions.html.
SELECT can also be used to retrieve rows computed without reference to
any table.
URL: http://dev.mysql.com/doc/refman/5.5/en/select.html
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