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SELECT - col_spec

Quick Reference

Other versions: 7.31 | 7.40 | 7.54

Syntax


... sql_exp ...

Alternatives

1. ... col
2. ... literal | @dobj | @( expr )
3. ... sql_func | sql_arith | sql_cast | sql_string | sql_case

4. ... sql_agg
5. ... sql_win

Effect

Specifies columns in the SELECT list of the SELECT clause of a query. The specified columns are used to construct the results set of a query from individual columns. Each column is specified using an SQL expression sql_exp. Any SQL expressions and parentheses can be used

Each SQL expression uses its arguments to determine a value (with a data type dependent on the expression) and places this value in the column of the results set. The corresponding data host variable after INTO or APPENDING be a suitable choice.

To be able to evaluate the result of SQL expressions except for individual column specifications in INTO|APPENDING CORRESPONDING FIELDS, INTO ...@DATA(...), and ORDER BY, an alias name must be defined usingAS, which is then used by these additions.

The following sections discuss the special characteristics of the various SQL expressions.


Note

Certain SQL expressions can be calculated in the table buffer. If any other SQL expressions are used, table buffering is bypassed.

Alternative 1

... col

Effect

Direct specification col of an individual column of a data source as an elementary SQL expression. If the name of a data source is specified directly, the relevant content is provided in the corresponding column of the result set. The data type of a column in the results set is the data type of the corresponding component in ABAP Dictionary.

Note the following special conditions

  • If required, the specified column can contain a path expression for CDS associations or CTE associations. If the addition CORRESPONDING or an inline declaration @DATA(...) is used in the INTO clause, any columns specified using a path expression must have an alias name alias defined using AS.
  • If the value of a column of type LRAW or LCHR is read, the associated length field of type INT2 or INT4 must also be read and specified in the list in front of the column of type LRAW or LCHR.


Notes

  • A column can be specified more than once.
  • Directly specified columns can only be listed in the obsolete form of space-separated lists.
  • It was possible to specify individual columns directly before the introduction of SQL expressions, so this does not lead to the strict mode of the syntax check, which is otherwise brought about by the SQL expressions.


Example

Specifies the columns CARRID, CARRNAME, and URL of the database table SCARR directly.

SELECT FROM scarr 
       FIELDS carrid, carrname , url 
       INTO   TABLE @DATA(itab).

Alternative 2

... literal | @dobj | @( expr )

Effect

Specification of a literal literal, host variable @dobj, or host expression @( expr ) as an elementary SQL expression. These are values of the ABAP program that are determined before the query is executed in ABAP and are transferred to the database system, where they are inserted into the result set as a column. A column defined in this way contains the same value in all rows of the result set.


Notes

  • The restrictions on elementary SQL expressions apply with respect to the data types that can be used. More specifically, no strings can be specified and any host variables specified as field symbols or formal parameters cannot have generic data types.
  • It can be a good idea to specify a literal, a host variable, or a host expression as an elementary expression of a SELECT list whenever a defined value is assigned to a column of a results set that is not read from the database.
  • Specifying a constant or a literal as the only element of a SELECT list is one way of defining whether data in a selection exists without having to read data from the database.
  • Literals, host variables, and host expressions are handled as real SQL expressions in the SELECT list, which result in a strict mode of the syntax check and cannot be used in combination with FOR ALL ENTRIES.


Example

Specification of the constant abap_true from the type group ABAP to determine whether a specific row exists.

SELECT SINGLE 
       FROM scarr 
       FIELDS @abap_true 
       WHERE carrid = '...' 
       INTO @DATA(flag). 
IF flag IS INITIAL. 
  RETURN. 
ENDIF.

Alternative 3

... sql_func | sql_arith | sql_cast | sql_string | sql_case

Effect

Specification of a non elementary SQL expression in the form of a built-in function sql_func, of an arithmetic expression sql_arith, cast expression sql_cast, string expression sql_string, or case distinction sql_case. The values of these expressions are calculated in the database. The rules and restrictions described for these apply. The values of the data source columns specified as operands are the selected values of the current row.


Note

The non elementary SQL expressions result in a strict mode of the syntax checl and cannot be used in combination with FOR ALL ENTRIES. No LOBs can be edited in the expressions.


Example

Using a non elementary SQL expression as a column specification.

SELECT CONCAT_WITH_SPACE( carrname && ' (' && carrid && '),', url, 1 ) 
       FROM scarr 
       INTO TABLE @DATA(itab).

Alternative 4

... sql_agg

Effect

Specifies an aggregate expression sql_agg, in which a column of a data source or an SQL expression is specified as an argument of an aggregate function. An aggregate function uses the values from multiple rows of the specified column or SQL expression to calculate a single value (with a data type that depends on the aggregate function), and then places this value in the column of the results set.

The following rules apply when aggregate expressions are used in the SELECT list:

  • If aggregate expressions are used, any column names that are not specified within an aggregate expression must be specified after the addition GROUP BY. The aggregate functions evaluate the contents of the groups defined by GROUP BY in the database system and pass the result to the merged rows of the results set.
  • If the addition FOR ALL ENTRIES is used before WHERE, no aggregate expressions can be used except COUNT( * ). In cases like these, the aggregate expression is not evaluated in the database, but is emulated on the AS ABAP.
  • If columns are only used within aggregate expressions in the SELECT list, the results set has just one row and the addition GROUP BY is not required. If a non-table-like target area is specified after INTO for aggregated-only columns and without the addition GROUP BY after a single SELECT statement (which means not in the case of multiple statements joined using UNION), the statement ENDSELECT cannot be specified (as is also the case when using the addition SINGLE). If the aggregate expression COUNT( * ) is not used, an internal table can be specified after INTO regardless of the addition GROUP BY and the first row of this table filled.
  • In the case of aggregated-only columns without GROUP BY, the results set also contains a row if no data is found in the database. If COUNT( * ) is used, the column in question contains the value 0. The columns of the other aggregate functions contain initial values. This row is assigned to the data object specified after INTO and, unless COUNT( * ) is used only statically and an alias name is not specified, sy-subrc is set to 0 and sy-dbcnt is set to 1.
  • If COUNT( * ) is used as the only static column specified and an alias name is not specified using AS and GROUP BY is not specified at the same time, the addition INTO can be omitted. The number of selected rows can then be taken from the system field sy-dbcnt. If more than 2,147,483,647 rows are selected, sy-dbcnt contains the value -1. If no data is found on the database, sy-dbcnt is set to 0 and sy-subrc is set to 4.


Notes

  • Aggregate expressions cannot be specified together with data_source~* in the comma-separated list.
  • If aggregate expressions are used as operands of SQL expressions, the same rules apply as if they were specified directly.
  • It was possible to specify individual aggregate expressions directly before the introduction of SQL expressions, so this does not lead to the strict mode of the syntax check, which is otherwise brought about by SQL expressions.


Example

Gets the number of rows in the database table SCARR.

SELECT FROM scarr 
       FIELDS COUNT( * ) 
       INTO   @DATA(wa).

Alternative 5

... sql_win

Effect

Specifies a window expression sql_win in which a window function is applied to a window of the results set. Window expressions can only be specified in the SELECT list.