github.com/octohelm/storage@v0.0.0-20240516030302-1ac2cc1ea347/pkg/sqlbuilder/alias.go (about)

     1  package sqlbuilder
     2  
     3  import (
     4  	"context"
     5  )
     6  
     7  func Alias(expr SqlExpr, name string) SqlExpr {
     8  	return &exAlias{
     9  		name:    name,
    10  		SqlExpr: expr,
    11  	}
    12  }
    13  
    14  type exAlias struct {
    15  	name string
    16  	SqlExpr
    17  }
    18  
    19  func (alias *exAlias) IsNil() bool {
    20  	return alias == nil || alias.name == "" || IsNilExpr(alias.SqlExpr)
    21  }
    22  
    23  func (alias *exAlias) Ex(ctx context.Context) *Ex {
    24  	return Expr("? AS ?", alias.SqlExpr, Expr(alias.name)).Ex(ContextWithToggles(ctx, Toggles{
    25  		ToggleNeedAutoAlias: false,
    26  	}))
    27  }
    28  
    29  func MultiMayAutoAlias(columns ...SqlExpr) SqlExpr {
    30  	return &exMayAutoAlias{
    31  		columns: columns,
    32  	}
    33  }
    34  
    35  type exMayAutoAlias struct {
    36  	columns []SqlExpr
    37  }
    38  
    39  func (alias *exMayAutoAlias) IsNil() bool {
    40  	return alias == nil || len(alias.columns) == 0
    41  }
    42  
    43  func (alias *exMayAutoAlias) Ex(ctx context.Context) *Ex {
    44  	e := Expr("")
    45  	e.Grow(1)
    46  
    47  	RangeNotNilExpr(alias.columns, func(expr SqlExpr, i int) {
    48  		if i > 0 {
    49  			e.WriteQuery(", ")
    50  		}
    51  		e.WriteExpr(expr)
    52  	})
    53  
    54  	return e.Ex(ContextWithToggles(ctx, Toggles{
    55  		ToggleNeedAutoAlias: true,
    56  	}))
    57  }