SINGLE SELECT Statement (single_select_statement) 
A SINGLE SELECT statement (single_select_statement) specifies a single-row result table and assigns the values of this result table to parameters.
Structure
Syntax
<single_select_statement> :: SELECT [<distinct_spec>] <select_column>,... INTO <parameter_spec>,... FROM <from_table_spec>,... [<where_clause>] [<group_clause>] [<having_clause>] [<lock_option>]
Explanation
The number of rows in the result table must not be greater than one. If the result table is empty or contains more than one row, corresponding messages or error codes are issued and no values are assigned to the parameters specified in the parameter specifications. If the result table is empty, the message 100 – Row not found is displayed.
If the result table contains just one row, the values of this row are assigned to the corresponding parameters. The FETCH statement rules apply for assigning the values to the parameters.
The order of the GROUP and HAVING clauses is random.
A LOB column can be specified in a selected column select_column in the uppermost sequence of selected columns in a SINGLE SELECT statement only if the DISTINCT specification (distinct_spec) DISTINCT was not used there.