| 1 | #pragma once | 
| 2 |  | 
| 3 | #include <Parsers/IParserBase.h> | 
| 4 |  | 
| 5 | namespace DB | 
| 6 | { | 
| 7 |  | 
| 8 | /** CASE construction | 
| 9 |   * Two variants: | 
| 10 |   * 1. CASE expr WHEN val1 THEN res1 [WHEN ...] ELSE resN END | 
| 11 |   * 2. CASE WHEN cond1 THEN res1 [WHEN ...] ELSE resN END | 
| 12 |   * NOTE Until we get full support for NULL values in ClickHouse, ELSE sections are mandatory. | 
| 13 |   */ | 
| 14 | class ParserCase final : public IParserBase | 
| 15 | { | 
| 16 | protected: | 
| 17 |     const char * getName() const override { return "case" ; } | 
| 18 |     bool parseImpl(Pos & pos, ASTPtr & node, Expected & expected) override; | 
| 19 | }; | 
| 20 |  | 
| 21 | } | 
| 22 |  |