/sap-abap-cds

ABAP CDS Expressions Reference

Complete reference for expressions, operators, and conditional logic in ABAP CDS views.

Source: https://discoveringabap.com/2021/10/13/exploring-abap-on-hana-7-expressions-operations-in-cds-views/

Version Note: $session.user, $session.client, $session.system_language require 7.40 SP08. $session.system_date requires 7.51+. CASE, arithmetic, and CAST expressions are available from 7.40 SP08.

Projection List Elements

The projection list (SELECT list) can contain:

Field References

Simple Field

{
  matnr,
  maktx
}

With Source Prefix

{
  source.matnr,
  source.maktx
}

With Alias

{
  matnr as MaterialNumber,
  maktx as Description
}

Key Fields

{
  key matnr,
  key spras,
      maktx
}

Literals

Typed Literals

{
  'EUR' as DefaultCurrency,          -- Character
  100 as DefaultQuantity,            -- Integer
  123.45 as DefaultPrice,            -- Decimal
  abap.dats'20241115' as FixedDate   -- Typed date
}

Untyped Literals

{
  'Active' as StatusText,
  0 as InitialValue
}

Note: Literals require an alias.

Session Variables

Access ABAP system fields:

{
  $session.user as CurrentUser,
  $session.client as ClientId,
  $session.system_language as Language,
  $session.system_date as Today
}

Comparison Operators

Basic Operators

BETWEEN Operator

where date between '20240101' and '20241231'

-- Equivalent to:
where date >= '20240101' and date <= '20241231'

IN Operator

where status in ('A', 'B', 'C')

-- Equivalent to:
where status = 'A' or status = 'B' or status = 'C'

NULL Checks

where description is null
where description is not null

Pattern Matching (LIKE)

where name like 'SAP%'        -- Starts with SAP
where name like '%GmbH'       -- Ends with GmbH
where name like '%Partner%'   -- Contains Partner
where code like 'A_B'         -- A followed by any char, then B

Escape Character:

where name like '%10#%%' escape '#'  -- Contains literal %

Arithmetic Operations

Basic Arithmetic

Examples

{
  quantity * unit_price as LineTotal,
  gross_amount - discount as NetAmount,
  total / 100 as Percentage,
  -balance as NegatedBalance
}

Operator Precedence

1. () Parentheses
2. - Negation
3. *, / Multiplication, Division
4. +, - Addition, Subtraction

-- Without parentheses: 10 + (5 * 2) = 20
10 + 5 * 2

-- With parentheses: (10 + 5) * 2 = 30
(10 + 5) * 2

CASE Expressions

Simple CASE

Compare single expression to multiple values:

case status
  when 'A' then 'Active'
  when 'I' then 'Inactive'
  when 'D' then 'Deleted'
  else 'Unknown'
end as StatusText

Searched CASE

Multiple independent conditions:

case
  when amount > 10000 then 'High'
  when amount > 1000 then 'Medium'
  when amount > 0 then 'Low'
  else 'Zero'
end as AmountCategory

Nested CASE

case type
  when 'S' then
    case status
      when 'A' then 'Sales Active'
      when 'C' then 'Sales Closed'
      else 'Sales Other'
    end
  when 'P' then 'Purchase'
  else 'Other'
end as TypeDescription

CASE with Calculations

case indicator
  when 'H' then amount
  when 'S' then -amount
  else 0
end as SignedAmount

CASE in WHERE Clause

where case
        when type = 'A' then priority
        else 0
      end > 5

Note: Using CASE in WHERE clause is useful for conditional filtering without creating intermediate computed fields. However, it may impact query performance compared to post-filtering in ABAP or using separate WHERE conditions. Use judiciously on large datasets.

Logical Operators

AND

Both conditions must be true:

where status = 'A' and type = 'S'

OR

At least one condition must be true:

where status = 'A' or status = 'B'

NOT

Negates condition:

where not status = 'D'
-- Equivalent to: where status <> 'D'

Complex Logic

where (status = 'A' and type = 'S')
   or (status = 'B' and priority > 5)

Precedence

1. NOT
2. AND
3. OR

Use parentheses for clarity:

-- Unclear:
where a = 1 or b = 2 and c = 3

-- Clear:
where a = 1 or (b = 2 and c = 3)

Aggregate Expressions

Functions

GROUP BY

Required for non-aggregated fields:

{
  customer,
  sum(amount) as TotalAmount,
  count(*) as OrderCount
}
group by customer

HAVING

Filter aggregated results:

{
  customer,
  sum(amount) as TotalAmount
}
group by customer
having sum(amount) > 10000

Complete Example

define view Z_CUSTOMER_SUMMARY as select from sales_order
{
  customer,
  sum(amount) as TotalSales,
  avg(amount) as AvgOrderValue,
  min(order_date) as FirstOrder,
  max(order_date) as LastOrder,
  count(*) as OrderCount,
  count(distinct product) as UniqueProducts
}
group by customer
having count(*) >= 5

Path Expressions

Navigate through associations:

Basic Path

_Customer.name1 as CustomerName

Multi-level Path

_Order._Customer._Country.name as CountryName

Path with Filter

_Items[ItemNumber = '000010'].Material as FirstMaterial

Cardinality Indicator

When filter reduces to single result:

_Items[1: Status = 'A'].Quantity as ActiveQty

Conditional Navigation

Combine CASE with paths:

case
  when type = 'C' then _Customer.name1
  when type = 'V' then _Vendor.name1
  else 'Unknown'
end as PartnerName

NULL Handling

COALESCE

Return first non-null value:

coalesce(override_price, standard_price, 0) as EffectivePrice

CASE with NULL

case
  when field is null then 'Not Set'
  else field
end as SafeField

Arithmetic with NULL

NULL in arithmetic produces NULL:

-- If discount is NULL, result is NULL
price - discount as NetPrice

-- Safe version:
price - coalesce(discount, 0) as NetPrice

Type Conversion

Implicit Conversion

Some conversions happen automatically.

Explicit CAST

cast(numeric_field as abap.char(10)) as TextField,
cast(char_field as abap.int4) as IntField,
cast(amount as abap.curr(15,2)) as FormattedAmount

Common Type Conversions

Best Practices

1. Use parentheses: Clarify complex logic
2. Handle NULL: Use COALESCE or CASE
3. Alias expressions: Always name calculated fields
4. Type consistency: Ensure CASE branches return same type
5. Performance: Simple expressions perform better

Documentation Links

• ABAP Keyword Documentation — CDS DDL: CDS View Entity, sql_functions: https://help.sap.com/doc/abapdocu_latest_index_htm/latest/en-US/abencds_f1_builtin_functions.htm
• Discovering ABAP - Expressions: https://discoveringabap.com/2021/10/13/exploring-abap-on-hana-7-expressions-operations-in-cds-views/

Last Updated: 2025-11-23